A characterization of the norm of an Azumaya algebra of constant rank through the divided powers algebra of an algebra Dieter Ziplies — 1986 Beiträge zur Algebra und Geometrie = Contributions to algebra and geometry
Generators for the divided powers algebra of an algebra and trace identities Dieter Ziplies — 1987 Beiträge zur Algebra und Geometrie = Contributions to algebra and geometry