Identification books.

[Pippers]

Hey, when I was younger, I used to have piles of these pocket identification books of military planes, tanks, etc. I've been trying to track something like this down, and was wondering if anyone here could point me in the right direction of:

The Essential Vehicle Identification Guide: Western Allied Tanks, 1939-45 (The Essential Vehicle Identification Guide) [Hardcover]
David Porter (Author)

But in a more pocket size? Particularly WW2 subject material. Mostly because I'd like to read up quick stats of unit types I encounter in PG.