I would check into what online resources (like databases) your library has. Local libraries can have good stuff, but since you mentioned the price of textbooks I’m guessing you might be enrolled in some level of school? My college had some great online databases (EbscoHost was my favorite…lots of scholarly articles). Also try Google Scholar. When you’re looking online, try to stick with sites that end in .edu and .org, since they are either scholarly or non-profit…both of those tend to have more reliable info. Obviously books are good, but small libraries make that harder. If you’re really stuck, you could try sending an email personally to a professor somewhere, or to a field expert. Sometimes they answer, sometimes they don’t, but it’s worth a shot.
Also play around with keywords if you’re having trouble finding what you need. Sometimes I have to start broad and fine tune keywords as I find more info on my topic. It can be quite the sleuthing adventure sometimes. xD
I hope that helps!
Ambiverted INFP. Scribbles all the words. Names the plant friends. Secretly Edna the Piguirrel.