A bibliography or list of references can help you to learn the source of the author's information. Consider these factors and then decide if and how you would like to use this author's work in research. Based on your evaluation, you may decide to not use some of the sources or find additional sources. Don't get frustrated. The purpose of writing papers, speeches, and projects is for you to learn.
Research is just part of that learning process.
It is possible that you may have to use several library resources or formats of information to get the information you need. The best thing to do is allow yourself plenty of time for research and ask your instructor or a librarian for help if you run into any problems.