Isomorphism of Endomorphism Algebras over Complete Discrete Valuation Rings. Warren May — 1990 Mathematische Zeitschrift
Outer automorphisms of endomorphism algebras Warren May — 2006 Colloquium Mathematicae Commutative rings over which no endomorphism algebra has an outer automorphism are studied.
Independence in Completions and Endomorphism Algebras. Rüdiger Göbel; Warren May — 1989 Forum mathematicum