Now that you now what to look for in a credible source, let's talk about what are considered credible sources.
Can I find credible sources at my university's library?
In general, most of what you find through your university's library, whether it is a book, scholarly journal article, music recording, CD, DVD, e-book, etc. will be a credible source. However, you should check the publisher of the information: did it come from an academic or university press? Look up the publisher's name to learn more about the materials they publish. However, be aware that your university library may also have popular media which may not be a credible source of information. Be sure to answer the questions in the What Makes a Source Credible? section to verify credibility.
Are social media posts, blogs, and videos found on sites like Youtube, Vimeo, etc. credible sources?
That depends. The Associated Press has started crediting blog posts in their articles, but that does not guarantee that the blog is reliable or a credible source of information. Always verify that the source is credible before you use it in an academic paper.
What about Wikipedia? Is that a credible source?
According to Wikipedia's Introduction, "anyone can edit" pages in the site. This means that people who are not experts in a field can update a page to reflect whatever information they feel to be true. Wikipedia does say that references should be used whenever possible in their Introduction, and they do have a policy, also outlined briefly in the Introduction, that states that any edits made to controversial pages should be discussed before they are made. You should treat a Wikipedia article as a suspect source--it is more than likely not going to be a credible source to use in an academic research paper.
However, you can use a Wikipedia article to find reliable sources. If you do a search for your topic on Wikipedia, you will see at the bottom of the article several sections that you can use to find more sources: the Notes, References, Further Reading, and External Links. While each of these sections may not be present in each article, if they are present, you can use the links provided to find the article used as a reference and verify that that source is a credible source.
What about Personal Interviews?
If you can contact someone who is an expert in the field you are researching, you can conduct an interview with them to get more information. Do some research into your expert's background, using the questions in the Authority section to help you determine their expertise in the field.