Bettireihen von Faserprodukten lokaler Ringe. Andreas Dress; Helmut Krämer — 1975 Mathematische Annalen
Binary Moore-Penrose inverses of set inclusion incidence matrices. Krämer, Helmut — 2001 Séminaire Lotharingien de Combinatoire [electronic only]
Eigenspace decompositions with respect to symmetrized incidence mappings. Krämer, Helmut — 1998 Séminaire Lotharingien de Combinatoire [electronic only]
Inversion of incidence mappings. Krämer, Helmut — 1997 Séminaire Lotharingien de Combinatoire [electronic only]