According to Excelsior's site, it looks like there is a new edition of the John Weeks Population book that is being recommended, the tenth edition, which is ISBN# 0495096377. I have the ninth edition, which I found used at Amazon.com, and the ISBN for that is 0534627692. Hope that helps.
[COLOR="Navy"]BS Liberal Arts
Excelsior College
MS Psychology
California Coast University[/color]
Excelsior College
MS Psychology
California Coast University[/color]