Hellboy and others...
Mike Mignola has done extensive work with the paranormal in the immediate postwar era in his Hellboy comics, which I have used for ideas in the past. Also Jack Higgins-- no mysticism there, but a hell of a good read and easily pirated plot elements. Check out Cold Harbour, The Eagle Has Landed and To Catch a King. I'm especially fond of his recurring characters and their various motivations. One of your players could have a lot of fun with a character modelled after Liam Devlin, Higgins' Irish agitator who was tapped by the Germans as their "5th column" man on the ground for a secret invasion of England in The Eagle Has Landed.
I listed a ton of films in the other WWII thread in this forum... all this talk of WWII is making me consider giving it a go myself!