NiedHF,
If you're still looking for information on the Fokker EV/DVIII wing, The May 1980 issue of World War I Aeroplanes (Issue #79) has a fair bit of material devoted just to the wing. See the link:
http://www.ww1aeroplanesinc.org/docs/back_issues.htm
I also read of the divergence issue, perhaps also in Bisplinghoff, Ashley, and Halfman some years ago. Back when I was doing my graduate work (late '80s) I remember my professor recieving a report that originated in Germany that contained a history of aeroelasticity and/or unsteady aerodynamics. It may have come from one of the German Univs., but the text was in English. To the best of my recollection the author's name was Bublitz, and report was written in the 80's. I was fascinated with some accounts of possible aeroelastic problems with some WWI aircraft. I remember Albatros fighters and Handley-Page bombers mentioned, probably the Fokker cantilever wing also.
I did a quick Google search using the words "Bublitz" and "Aeroelasticity" and got reference to a report by Dr. Peter Bublitz in a discussion at a technical meeting. Not too much to go on, but perhaps a start.
What you're researching sounds interesting. If I can be of help we can take this discussion offline.
Best Regards.