It's a good idea to double-check the source of a quotation. You might try searching in Google Books, or see some of the suggestions offered by Quoteland.
Or ask a librarian to help! (Tracking down the source of a quotation can sometimes be a tricky challenge.)
There are a number of quotation websites, but here are a few recommended ones:
For even more books of quotations, check out the PN6081 section of the library's Print Reference collection (2nd floor).