Below is a list of the sources I used and use for my Normandy research. Not all are directly related to Normandy, but I try to stay focused as much as I can and provide you with a list of things to check out yourself too. If you have any additions that you think should be in this list, let me know at francois@fssupport.com !

PictureTitle and AuthorPublisher/shop
The Normandy Invasion: June 1944 - Looking down on War, by Roy M. StanleyPen & Sword Books

D-Day Operations Manual by Jonathan FalconerHaynes Publishing

50 Aerodromes pour une Victoire by Francois RobinardHeimdal Publishing
The Atlantic Wall by J.E. Kaufmann e.o.Pen & Sword Books