Minimal singularities for representations of Dynkin quivers. Klaus Bongartz — 1994 Commentarii mathematici Helvetici
Indecomposables Over Representation-Finite Algebras Are Extensions of an Indecomposable and a Simple. Klaus Bongartz — 1984 Mathematische Zeitschrift
Degenerations for representations of tame quivers Klaus Bongartz — 1995 Annales scientifiques de l'École Normale Supérieure