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How to Choose Reliable Resources: Home

Determining the Reliability of a Resource

Not sure where to begin?

 

Not sure where to begin?

We recognize that many students will begin their search by performing an internet search for their topic.  So, let's learn how to determine if the information you find on the web is appropriate to use in your research. 

  

Let this be a beginning step in your research, not the only step.

Is the resource you've found on the web a good resource?  How can we tell?

  • Use the SIFT method to determine the credibility of information found on the web.
    • Stop - do not engage with the text until you get enough context about the text to determine if it is worth engaging with.
    • Investigate the source -
      • who is the author? 
      • what is the purpose of the source?
      • is it possibly written with a bias?
      • has it been reviewed and approved by experts in the field of study?
    • Find better coverage - find other resources about the topic from reliable sources.
    • Trace claims, quotes and media to the original context - backward searching.

Modified from Mike Caulfield's SIFT (Four Moves), which is licensed under a Creative Commons Attribution 4.0 International License.

Why might an Internet search be a good place to start? Discovery 

  • Learn the basics about your topic
  • Use what you have learned to inform your research.
  • Create a list of keywords related to your topic.
  • Develop your keywords in relation to what you want to learn about your topic.
  • Use the library's databases to provide direct access to academic, peer-reviewed materials.

 

What makes a good resource?

 

What makes a good resource?

Relevancy - Does this source deal specifically with your topic?

Scope - Does this source only mention your topic briefly or does a substantial portion of the resource discuss your topic?

Currency (as applicable to the topic) - When was this piece written? Does the age of the source affect its relevancy to your topic?

Credibility/Reliability - Who is the author?  Do they have the authority to speak about this topic?  What are the author’s credentials?  Has this resource been reviewed by other experts in this field of study?  

Purpose - Informative vs. Persuasive. What is the intention of this source? Is the author trying to persuade you or is the author presenting information? Is there a bias you should be mindful of?

 

The C.R.A.P. Test:

 

When choosing a resource, it is important to determine the credibility and reliability of that resource.
To do that, we recommend the C.R.A.P. test: 

Currency 

  • What is the publication date?
  • and how does this date impact your topic of research?
    • Remember, newer doesn't always mean better.  The need for currency depends heavily on the topic of your paper. 
    • If you are evaluating a website, the publication or copyright date will help you determine if the site is current.  If you can't find a date on a website, beware; the information on the site might very well be out-of-date.  Broken links are another sign that the site has not been updated recently.  

Relevancy

  • Does this resource actually deal with your topic?  
    • Be careful that you aren't choosing a resource just because it has your keyword somewhere in the title or contents. Make sure the work has a substantial portion that directly addresses your research topic.
    • Ask yourself, "Does the resource primarily deal with the topic I am researching?"

Authority/Accuracy

  • Who is the author of the resource?  
  • Do they have substantial academic or professional experience and credentials that give them the authority to speak on this topic?
  • Does the resource provide references for the included information?
  • Was the resource published by a reputable organization?
  • When you are evaluating a website, web addresses that end in .gov and .edu are typically more authoritative than .com sites.  

Purpose/Point-of-view

  • Why was this resource written?  To inform?  To persuade?  
  • Consider the sponsoring organization associated with the resource. 
  • Be aware of any bias that the author may have toward your subject that could taint the authority and reliability of the information provided in their work.

 

 

Primary and Secondary

 

Sources are divided into two main groups; primary and secondary.  

  • Primary sources provide a firsthand account or insider's look at a specific person, a specific time period, or a specific event.  If a primary source could speak to us it would say, “I was there; this is my experience or my experiment.”  Examples of primary sources include diaries, personal journals, autobiographies, memoirs, personal correspondence, interviews, speeches, newspaper articles or news footage from a specific time in history, official records, original photographs, creative works such as plays, poetry, music, or art, and also original research data.  Primary sources can be documents, photographs, film or video footage, and objects/artifacts. Please note that primary source does not necessarily equal factual source.  Primary sources provide firsthand accounts of an event, experience, or experiment.  It is up to you, the researcher, to evaluate each of those accounts individually to build an informed, knowledgeable, and well-rounded assertion about your topic.   

 

  • A secondary source is an interpretation or analysis of one or more primary sources.  If a secondary source could speak to us it would say, “I wasn’t there but I have studied the topic and these are my thoughts on the matter.”  Examples of secondary resources include such publications as biographies, commentaries, criticisms, textbooks, articles, and critical essays.  

Example:   

       

The first book on the left, I am Not Spock, was written by Leonard Nimoy and is his personal account of his experiences of portraying the character of Spock in the television series Star Trek.  The next book, Star Trek: Movie Memories, was written by William Shatner who portrayed the character of Captain James T. Kirk and discusses his experiences during the creation of the Star Trek films.  Each of these sources says to us, "I was there; this is my experience."  These are primary sources.

The last book, Star Trek as Myth, is a collection of essays about Star Trek.  This book is comprised of the different authors' interpretations and analysis of the mythology of the television series and films.  This book says to us, "I wasn’t there, but I watched Star Trek and these are my thoughts on the matter."  This book is a secondary resource.

 

What is Peer-Reviewed

 

Peer-reviewed simply means that the article’s content has been checked by other experts in that specific field of study for accuracy and reliability.  These resources are also often referred to as scholarly articles or academic articles.

5 Clues that the article is peer-reviewed:

  1. References – always look for a list of works cited, a bibliography, or a reference list
  2. Author – educational and professional credentials provided
  3. Abstract – a short summary highlighting the content of the article
  4. Audience – content written using specialized terminology
  5. Graphs and Charts – visually communicated empirical data

 

Evaluation Criteria Tutorials

 

 

A Note About Wikipedia

 

Courtesy of the MIT Libraries

 

Simple Strategies

The Internet allows people to create and to share information in ways that once seemed possible only in science fiction. At the same time that we can benefit from the open nature of the Internet, it's sometimes hard to decide what online information to trust and to use.

We'll offer some simple, evidence-based strategies for evaluating the credibility of online sources, as well as reading critically. More specifically, we’ll teach you about “lateral reading,” the practice of doing a quick initial evaluation of a website by spending little time on the website and more time reading what others say about the source or related issue. Lateral reading is used commonly by fact checkers.

These strategies will help you look beyond less important surface features of a web source (for example, how professional it looks or if it's a .org), and think more carefully about who is behind the source, what their purpose is, and how trustworthy and credible they are. 

On this page we’ll introduce you to several lateral reading strategies and concepts. On the guide’s other pages (see the navigation menu) we’ll share additional source evaluation strategies and learning resources.

This guide draws largely on research from the Stanford History Education Group and on teaching materials from Mike Caulfield's SIFT approach and his Web Literacy for Student Fact-Checkers.

Image credit: “200 pair telephone cable model of corpus callosum.” By brewbooks. Creative Commons license: Attribution-ShareAlike 2.0 Generic (CC BY-SA 2.0)

 

Click Restraint

 

One important part of lateral reading is click restraint. When you practice click restraint, you don’t immediately click on the first search results. Instead you scan a search results page, looking at things like the title, source description, and featured sections, before deciding what sources to examine. This helps you to get a fuller picture of the coverage available on that source, as well as to look for sources that don’t come from the original source. 

Fact checkers exercise click restraint: they recognize that some sources may not be the most reliable ones and look for trusted coverage. Doing this will help you avoid “rabbit holes” and misleading information. Considering the results page as a whole can also give you insight into the source. For example, if many of the sources appear to be highly partisan or emotionally charged, the original source may be about a polarizing issue, or the source itself may be polarizing. 

This short video from the Stanford History Education Group illustrates the importance of click restraint and why you shouldn’t assume that the first search results are necessarily the most reliable or relevant ones. 

Video: How to Find Better Information Online: Click Restraint

 

SIFT: Web Evaluation

 

SIFT is a helpful acronym for initially evaluating source credibility. SIFT (from Mike Caulfield) stands for:

  • STOP. Pause and ask yourself if you recognize the information source and if you know anything about the website or the claim's reputation.
    If not, use the four moves (below) to learn more. If you start getting too overwhelmed during the other moves, pause and remember your original purpose.
  • INVESTIGATE the source.
    Take a minute to identify where this information comes from and to consider the creator's expertise and agenda. Is this source worth your time? Look at what others have said about the source to help with you these questions. (See the "Four Moves" below for more on investigating sources.)
    (For example, a company that sells health food products is not the best source for information about health benefits/risks of consuming coconut oil. A research study funded by a pharmaceutical company is also suspect.)
  • FIND trusted coverage.
    Sometimes it's less important to know about the source and more important to assess their claim. Look for credible sources; compare information across sources and determine whether there appears to be a consensus.
    Again, use the Four Moves below.
  • TRACE claims, quotes, and media back to the original context.
    Sometimes online information has been removed from its original context (for example, a news story is reported on in another online publication or an image is shared on Twitter). If needed trace the information back to the original source in order to recontextualize it. 

Modified from Mike Caulfield's SIFT (Four Moves), which is licensed under a Creative Commons Attribution 4.0 International License.

Later, when you determine that the site is worth your time, you can analyze the source's content more carefully.

 

Four Moves of Fact Checkers

 

There are numerous ways to "SIFT" (as described above). These "four moves" from Web Literacy for Student Fact-Checkers will help you "SIFT." 

When you first come across a web source, do a quick initial assessment, much like a fact-checker does. Fact-checkers don't spend too much time on a website; instead they quickly leave that site to see what others have said about the site.

  • "Check for previous work.": Has someone already fact-checked the claim or analyzed the research?
    (Search the Internet for other coverage on the claim. Consider where that coverage comes from.)
  • "Go upstream to the source.": Is this the original source of the information, or is this a re-publication or an interpretation of previously published work? Are you examining the original source? If not, trace back to it.
  • "Read laterally.": What are others have saying about the original source and about its claim?
    (For example, get other information about a website from other sources by searching Google for [WEBSITE URL] site: -[WEBSITE URL]
    • newyorktimes.com site: -newyorktimes.com
    • minimumwage.com site: -minimumwage.com
  • "Circle back.": If you hit a dead road, what other search terms or strategies might lead you to the information that you need? 

(Adapted from “Four Moves,” Web Literacy for Student Fact-Checkers, Mike Caulfield)

Later, when you determine that the site is worth your time, you can analyze the source's content more carefully. 

 

Lateral Reading

Quick Tips

 

Find what others say about a website. In Google search for "[WEBSITE URL] site: -[WEBSITE URL].

Examples:

  • newyorktimes.com site: -newyorktimes.com
  • minimumwage.com site: -minimumwage.com

The results will be from other websites. While some may have some relationship to the original domain, other sites can give insight into what others say about that site. 

Learn more about "web searching a domain" from Web Literacy for Student Fact-Checkers.

Check a Twitter account. Some Twitter accounts claim to be something they are not. To check the validity of a Twitter account:

  • Right-click on the Twitter handle (Twitter name) and select "Search Google for 'ACCOUNT NAME.'
  • On the Google results page select the "News" filter (top of the page). What do the results tell you about the Twitter account?

Learn more from this post by Mike Caulfield.

Check the origins of an image. If you find an image on a web page or a social media site like Twitter and are unsure of its authenticity, you can check its orgins with a reverse image search. In the Chrome browser right-click on the image and select Search Google for image. The image search results will show you other places where the image has appeared. Examine these results to see if there are any discussions about the trustworthiness or origins of the image.

Learn more from Web Literacy for Student Fact-Checkers.

Check your emotions. Do you have a strong reaction to the information you see (e.g., joy, pride, anger)? If so, slow down before you share or use that information.  

We tend to react quickly and with less thought to things that evoke strong feelings. By pausing, you give your brain time to process your initial response and to analyze the information more critically. Then you are better able to make use of the "Four Moves" described above.

 

Attribution

 

Creative Commons License CC-BY-NC-SA
This guide was created by Andrea Baer and Dan Kipnis at Rowan University and is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC-BY-NC-SA).

 

Closer Reading

The SIFT moves are great for initially evaluating online source credibility. Once you establish that a source is overall credible and useful for your work, you'll often want to read and evaluate the source more closely.

Criteria for Source Evaluation

Web Literacy for Student Fact-Checkers suggests paying close attention to three key aspects of a source: process, expertise, and aim. These criteria are based on Wikipedia's guidelines for evaluating source reliability.  

(Remember to use the four SIFT moves before doing this closer evaluation! If a source isn't credible, is may not be worth your time.)

  • Process: What processes are used to ensure accuracy?  
  • Expertise: What expertise does the content creator(s) have on the topic at hand?
  • Aim: What is the creator's purpose? Do they have an incentive to present accurate information? Are they likely to have a certain perspective on the topic?

Perspective and Bias

While some sources are primarily informative and others are more opinion-driven, almost all sources reflect a certain perspective (and along with it some degree of bias). This perspective influences what information the creator includes or excludes and how they present that information.

Rather than looking for sources that are completely free of any bias, recognize that most sources have some degree of bias. This is not necessarily a bad thing: people's personal experiences and viewpoints often provide important insights into an issue. Consider what the source creator's perspective is, what expertise they have on the topic, and what evidence they use to support their claims or arguments. Verify evidence by reading laterally and looking at other sources, including ones that may present a different perspective that is still well supported by evidence.

The Human Brain & Confirmation Bias

Our brains are wired to believe things that fit with our preexisting views and to disbelieve those things that challenge our views. This phenomenon is called confirmation bias.

Confirmation bias plays a powerful role in how we evaluate and use information. It's a major reason that misinformation easily spreads online. Learn more from this video about how confirmation bias influences us and we can counteract it.

Investigating Your Own Biases

Confirmation bias illustrates that we all have have our own perspectives and biases, which are influenced by own unique backgrounds and experiences. Being aware of your own biases can help you evaluate sources, arguments, and your own ideas more critically. Consider the strategies for minimizing bias that the journalists in this video share:

Reading Academic Resources

Academic texts can be especially challenging to read because they're written for experts in an area that is unfamiliar to most people. These strategies can help you navigate academic texts. 

First, remember that reading and writing are social. The author has something to add to a larger conversation. As you read, you are learning about that conversation, and you may later want to become part of the discussion. With the understanding that reading and writing are social, apply rhetorical reading strategies. Ask questions like these:

Author's purpose and audience: Who is the author? To whom are they speaking and why?

Clues into this include:

  • the publication source (e.g., academic journal, magazine, newspaper, book, website);
  • the publication's intended audience
  • language choice and style (e.g., formal or informal, use of specialized terminology)
  • use of evidence (e.g., references to research studies or to other publications, citation practices)

Your purpose: What do you want to gain from reading this source? This will likely influence how you read, such as whether you focus on certain sections more than others, if you take notes of certain things, etc.

Pre-reading: Before reading too closely, get a general understanding of what the source is about. Focus on areas such as the title, the abstract or summary (if available), section headings, and introduction.

Also reflect on how the source relates to your research interest. Identify important terms or concepts that are unclear and look them up if needed. With a general understanding of the source, you will be better able to comprehend it and to determine which areas on which to focus.

Active reading: Active reading strategies will help you better understand the source. Try:

  • highlighting important terms,
  • underlining the main argument,
  • making notes in your own words about key points from the text
  • identifying points of confusion (Don't worry if you don't understand everything; you can return to these areas later, after reading more and, if needed,  learning more about from other sources or from your instructor.

More strategies for before, during, and after reading (UNC-Chapel Hill Writing Center)

Reading strategies from students (UCLA Library)

Attribution

Creative Commons License CC-BY-NC-SA
This guide was created by Andrea Baer and Dan Kipnis at Rowan University and is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC-BY-NC-SA).

Images: Tracing the Source

Often images get reused on the web, and it's hard to know where they originated and if they have been manipulated or used to mislead. The SIFT strategies outlined on the Evaluating Online Sources page can help you investigate the origin of an image and if it is trustworthy.

The last part of SIFT may be especially helpful: TRACE claims, quotes, and media back to the original context. Start by asking from where the image originates. You may also need to INVESTIGATE the source(s) where you find the image. Consider questions like:  

  • Is the image from the webpage's creator or publisher or from somewhere else?
  • Do you trust the source/s on which the image appears? If you're unsure about that source, investigate it by seeing what others have said about the author or publication.
  • Is there a credited source or a link beside the image? If so, can that credited source be verified?  
  • Does the image - or do discussions of the image - appear elsewhere on the web? (Try Google Reverse Image Search, described below.)

Combining strategies: Keep in mind that sometimes you'll need to combine multiple strategies in order to assess the image's credibility (for example, examining who posted the image and assessing their credibility by looking at what others have said about them). The tools on this page can help in this process.

Google Reverse Image Search

Google's or Tineye's Reverse Image Search can help you determine an image's origins, which may or may not be the page where you found it. Reverse Image Searches looks for webpages that contain a specific image or similar images. If you find a related image, compare it and its origins with the image you're checking.

  • Search for an image from a website in the Chrome browser: Right-click on the image and select "Search Google for image." The results page will show you "Visually similar images" and potentially "Pages that include matching images." If there are other pages with matching images, look for the oldest page, which is more likely to e closest to the source from which the image originates. You can also try  Tineye's Reverse Image Search
    OR
  • Upload an image: In Google Images you can upload an image file and search for identical or similar images. Click Search by Image (the camera icon) and upload the image file you would like to search. (Note that Google stores the image file for 7 days; only upload a file you don't mind their having.) 

To see how you might combine multiple strategies see this example of using Google Reverse Image Search from Web Literacy for Student Fact Checkers.

Video: Search the History of an Image (Cntl-F, with Mike Caulfield)

Sorting Google Images by Date

When an image appears in multiple places online, it's helpful to sort by date in order to find the original source of the image. After running a Google Reverse Image Search, you can sort images by date: click the "Tools" option (top of page, next to the Settings), select the "Time" dropdown menu, then select "Custom range," and finally choose a range of dates or years. (If you have no idea around what year the image is from, Mike Caulfield recommends starting with 2009.) 

Learn more about from Web Literacy for Student Fact Checkers.

Viral Photos

Sometimes images are posted to social media sites like Twitter with no indication of their origins. Google Image Search (described above) can often help in identifying the image source, but you may also need other strategies.  

  • If available, Google an image's caption or headline, or Google a basic description of the image. (When selecting search terms and evaluating search results, keep in mind that viral images often have been misrepresented. You may find information about the image that doesn't match how the image was represented to you. 
  • If you find multiple references to an image published on different dates, pay the closest attention to the older content. Older content is more likely to be the original source, or at least closer to  the original source. 
  • When you find the original source, check the date. Does the date of the original image fit with how the image is represented in the reuse of the image?

Learn more about tracking viral photos from Web Literacy for Student Fact-Checkers.

Deepfake Videos

Deepfakes are fake media like images and videos in which an image of one person is replaced by another. Deepfakes can be surprisingly deceptive, even at this early stage in their development. The video below discusses the history of deepfakes and ways to detect them.

Video - Deepfakes: Can You Spot a Phony Video (Above the Noise, KQED)

It can be hard to spot deepfakes. Perhaps the most important thing is to be aware that they exist, so you can think critically about visual and media content that you encounter, as you consider their origins.

Here are some practical tips from the "Above the Noise" video above. To detect deepfakesl look for:

  • Facial framing: a straight forward-looking "mug shot"
  • Unrealistic-looking eyes and teeth
  • Strange blending on the outline of the face

You can also:

  • Look online for other sources that include the video. Consider those sources' credibility.
  • For YouTube videos, go to https://citizenevidence.amnestyusa.org/ and enter the YouTube URL. This site tracks misleading web content.
  • Slow down and reconsider sharing a video about which you have any questions. This allows time for professional fact checkers to spot the deepfake and inform others about it.

Checking a Social Media Account

How do you know if the person behind a Twitter or other social media account is trustworthy? In the video below fact checkers from Buzz Feed offer some tips on invesigating who is behind the account.. 

Video: "Evaluating Social Media Accounts" (Ctrl+F)

Key video points:

  • Check when the account was created.

  • Do a Reverse Image search on the profile image (right-click on the image). Do related images appear to use the same name?

  • If the account appears to be a famous person, look for a blue verification checkmark next to the username. You can also check things like spelling. 

Attribution

Creative Commons License CC-BY-NC-SA
This guide was created by Andrea Baer and Dan Kipnis at Rowan University and is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC-BY-NC-SA).

What is Media Bias?

Bias is "a particular tendency, trend, inclination, feeling, or opinion" about someone or something. When we discuss bias in media in the US, we are generally referring to conservative (also known as right) v. liberal (also known as left) bias, though there are many more ways to be biased and no one is truly free of bias.

Media Bias v. Fake News

Bias differs from fake news in that fake news is specifically untrue. Biased sources don't necessarily use lies, they just don't include the whole picture, only using the facts that support their viewpoint. By using only the facts that support their cause they are giving an incomplete and therefore inaccurate picture.

 

Confirmation Bias

Confirmation bias is tricky. As pertains to news, it basically says that we tend to seek out the sources that confirm our existing bias. We tend to watch just the conservative news, or just the liberal news depending on whether our own beliefs lean toward conservative or liberal.

Not only that, when we view centrist sources, we tend to think of them as leaning to the left or right rather then the center.

Which means we are not getting the whole picture of news and events in our world.

How do you get a more complete picture? Seek out sources that challenge your bias. In other words, get your news from the spectrum of bias: conservative, liberal, centrist.

Which Way Does Your News Lean?

Using rigorous methodology, the media bias chart evaluates popular media outlets and the way in which they tend to lean: centrist, conservative, or liberal. 

You can click/tap on the image to go to the full version of the chart.

Centrist News

Leans Left (Liberal) News

Leans Right (Conservative) News

How to Spot

When trying to spot bias, ask yourself these questions: 

1. What kind of information is it?
News? Opinion? Ad? Does it appeal to your emotions or does it make you think?
2. Who and what are the sources cited and why should you believe them?
 Is the source given? Is the source associated with a political party or special interest group?
3. What’s the evidence and how was it vetted?
What’s the evidence and how was it vetted? Is the source a document? Witness? Or is it hearsay/speculation?
4: Is the main point of the piece proven by the evidence?
Did the sources provided justify the conclusion or main point of the story?
5. What’s missing?
Was there an aspect or point that was not covered or unclear that you are left wondering about?

Based on American Press Institute.

Using Biased Sources

The authors of pro & con or biased articles, books, or other sources have a specific bias and are trying to persuade the reader of a specific point of view in contrast to most academic articles that typically focus on topics in an objective manner that is meant to inform the reader.

Here are some characteristics of persuasive or biased articles:

  • Generally the authors do not state their agenda or tell the reader if the they are for or against the topic. The reader has to determine if it is objective or persuasive.
  • The authors of these opinion or pro & con articles, books, or other resource may or may not have done research on the topic. The only way to tell is if the authors lists the sources used for their research.

If there is a list of sources used available, they are generally only those that support the agenda or argument of the author and do include those that support a different point of view.

How to Use Them

Opinion or pro & con articles, books, or other resources with bias are ideal to use in argumentative papers or presentations.

They can also be used for informative research assignments, but you have to be more careful so as not to produce an unintentionally biased paper or presentation that is meant to be objective.

Most importantly, you have to be able to recognize if your source is biased and if it is appropriate for your assignment. If you aren't sure, ask your instructor.

Attribution

Creative Commons License CC-BY-NC-SA
This guide was created by Kathy Park at College of the Mainland and is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC-BY-NC-SA).

Where to Get Your News

Fake news is everywhere. Media bias has become common. How do you sift through it all and find out what is true?

Use Library Databases & New Sites

You are more likely to get reliable news from library databases or Pulitzer Prize Winning News Sources. Even news sites and online news magazines are less likely to have fake news, though some are biased. More reliable biased sites let you know what their point of view is.

Use Multiple Sources

One of the best ways to determine accuracy is to use multiple sources. This is what scholars do. This is what faculty train college students to do when they write papers for courses. Scholars and faculty know that the more sources you review, the more likely you are to come to an accurate conclusion.

Review Sources

When you review your multiple sources, ask yourself things like:

  1. What does the author know about the subject?
  2. Does the author have an agenda?
  3. Where did the author get the information?
  4. When was the material written?
  5. Has the material been reviewed for publication?

If your sources don't have information about the author or it is not clear where the author got the information, it makes it very hard for you to evaluate. Sources that clearly state these things are generally more reliable.

Pulitzer Prize Winning News Sources

The Pulitzer Prize awards excellence in journalism for U.S. newspapers, magazines or news sites that publishes regularly.

Attribution

Creative Commons License CC-BY-NC-SA
Sections of this guide were created by Kathy Park at College of the Mainland and is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC-BY-NC-SA).