You also picked the most common, easy, low hanging fruit of a topic you possibly could have. Your professor will let you write on anything involving rodents. But you picked the history of Gerbil World. And so did everyone else. I suggested that you change your topic to something very close, but slightly more obscure. I pointed out the pile of books we still had on the (now closed) Hamster Gardens attraction.
Nope. You've already written your paper (with what sources?), and all you need is one book, because your professor requires an actual print (or electronic) book for your first paper. I check the local public library, but no dice.
Finally, in a moment of brilliance, I find a collection of essays vaguely related to Gerbil World. Here, I say. This is the last thing we have on your topic. Take it.
Not ten minutes later...
"I need a book on the history of Gerbil World..."
--Academic Madame Librarian