A lot of students have problems with finding the sources needed for their academic papers. Sometimes it is the main reason for their failure to accomplish the paper. There are a lot of solutions. First and the easiest one is that you can look for online versions of the book. Yes, it is pretty inconvenient to look through the book online, but it is worth it, when we are talking about getting a good grade. You can also register at one of the online libraries. The fee is low as it can get; you can pay for one visit or get a membership or a pass for a month for example. They have most of the books needed for the research. Some of them even allow downloading the PDF files of the books.