Don’t just drop in to the library to pick up the books you think you’ll need. Take 15 minutes to look at what you’ve got before dedicating study time to reading them. Check the table of contents, the first and last paragraphs of potentially useful chapters, and scan a few more pages to see if they can really answer the questions you have.
You’ll find some sources seem worthwhile because of their titles and abstracts, but they turn out to be off topic or, what’s worse, totally irrelevant to your assignment. If they don’t work out, it’s no problem, there are a ton of related books, articles, and first person sources who will help you complete your assignment.
In the end, having the right resource is better than having a handful of not quite right resources. Scrounging up the right text might take a lot longer than expected. Be patient, accept that sidetracking will happen, keep focused on finding an answer to your question and the time won’t matter as much.
If it’s worth doing, it’s worth doing well.