In order to present a trustworthy research argument, you need to use credible sources of information for your academic work.
Basic Evaluation Criteria:
Here are five questions to ask about all the information you're considering using for your research project:
Relevant - Does it answer your research question?
Current - Is the content presented current enough for your project?
Accurate - Is the information provided correct?
Authoritative - Does the author have expertise on the topic about which she is writing?
Objective - Is there bias or a slant given to the information provided?
You can feel pretty confident that books you get from the library and articles you find in the library's research databases are reliable and credible because you know those have gone through a traditional editorial process; someone or some group has checked all the facts and arguments the author made and then deemed them suitable for publishing. You still have to think about whether or not the book or article is current and suitable for your project but you can feel confident that it is a credible, reliable source.