@book{ title = {Gregorii 1. papae Registrum epistolarum}, author = {Gregorius <<papa ; 1.>>}, editor = {Ewald, Paul}, editor = {Hartmann, Ludo Moritz}, editor = {Ripr. facs. dell'ed.: Berlin : Weidmann, 1892 }, year = {1957}, edition = {Editio secunda lucis ope expressa}, address = {Berolini }, publisher = {Weidmann}, }