1: Find a book you want to cite on Google Books.
Copy the URL of the book from the address bar, and paste it below. Then press "Load". Example book.
Example book (copy and paste above): http://books.google.com/books?id=aqmAc2fFsAUC&pg=PA90
Try also: Wikipedia citation tool for DOI or The New York Times.
Also available from a user script: refToolPlus.
Made by Apoc2400. Send feedback to apoc2400 (at) gmail.com or my talk page. Using some html and js from refToolbar by Mr.Z-man. Bookmarklet for direct access from Google Books. Source code in Python.