Research, papers and preprints: 

• Eisensteinkohomologie und Dedekindsummen für $GL_2$ über  imaginär-quadratischen Zahlkörpern. (Eisenstein cohomology and Dedekind sums for $GL_2$ over imaginary quadratic number fields) Journal Reine Angewandte Math. 389 (1988), 90-121.
• With Maria Heep: Deligne' conjecture. In: Beilinson's conjectures on special values of L-functions. Perspectives in Mathematics 4 (1988), 37-42.
• An elementary identity in the theory of Hecke L-functions. Inventiones Mathematicae 95 (1989), 207-214. 
• Kohomologische Kongruenzen zwischen automorphen Darstellungen von $GL_2$. (Cohomological congruences between automorphic representations of $GL_2$.) Bonner Mathematische Schriften 245 (1993), 74 p.
•  With Joachim Ballmann and Rainer Weissauer: Remarks on the fundamental Lemma for stable twisted Endoscopy of Classical Groups.  Preprint 2001/2003       fule.pdf
•  On double coset decompositions for the group $G_2$.  Preprint 2003    G2alg.pdf
•  A twisted topological trace formula for Hecke operators and liftings from symplectic to general linear groups. Compositio Mathematica 148 (2012), 65 -- 120     Preprint: Top.pdf
•  Applications of a topological trace formula.  In preparation
• Eine Dimensionsformel füur Darstellungen von $Gl_n\times Gl_n$ Preprint 2010    Dimformel.pdf