When referencing books, please use the xbeta Amazon referral code. In case someone decides to purchase a book found on the wiki, a small percentage of the sale will go to help offset the costs of hosting the wiki. All that is required is the ISBN number of the book, which can be found via a quick search. Amazon referral links have the form
http://www.amazon.com/exec/obidos/ASIN/<ISBN>/xbeta-20where <ISBN> is the book’s ISBN-10 code.