"The Lockheed P38" by Warren Bodie
"Republic's P47 Thunderbolt" by Warren Bodie
"Mustang-Story of the P51 Fighter" by Robert Gruenhagen
"Mustang at War" Roger Freeman
"Fighting Mustang" William Hess
"The Messerschmitt 109-A Famous Fighter" by Heinze Nowarra
"The Fighting 109" by Uwe Feist, Norman Harms & Mike Dario
Squadron Signal publications does an "in Action" series that is aimed mostly at modellers, but has lots of good photos and info. They are done on just about every plane you can think of. The 109 is a two part set with the first 109s through the E model in one and the F til the end of the war models in the other.
There is a "Detail & Scale" series done by Bert Kinzey that is similar with many detail interior and exterior photos. The 38 set and the Mustang set are two books each.
There is a "Walk Around" series that can be found in most model shops and I know there is a 51 walk around and 190 walk around book.
The list goes on and on too

Dan/Slack