http://www.alsa.mil/library/alsb/ALSB%202008-1.pdf - pp 6-9
If you have access through your library to professional journals, check Small Wars & Insurgencies, Volume 21, Issue 3, 519 for an article titled "It's all the Rage" about Armor performance in insurgencies.

The following thread has lots of info and links that you may want:

http://council.smallwarsjournal.com/...ead.php?t=3951