PCCN Review Book

I'm planning on taking the PCCN exam this year, but I think I want to do independent study rather than a class.... any suggestions on good review books?

Thanks!!! =)
I remember taking months to study a little at a time using the essentials of progressive care from aacn. Do the chapters over a few days as it is complicated. They also have the dvd or mp3 which is more expensive than the book. A large portion is cardiac related. Passed with just that one book and also went to the book store and would read practice q&a for ccrn.http://www.aacn.org/DM/Products/Prod...&titleType=Any