WW1 German Links. David Gregory is a collector/researcher with a real interest in getting to the stories behind the men and their units. One of the first stops an Imperial Collector should make is at his site Colonel J has a great site that is not only about Pickelhauben but also has some interesting articles about the German Army in WW1 that are of interest to document researchers as well.
German WW1 allies.
Glenn J. has the premier site about the Austro Hungarian empire in the war. Well worth a visit or three.