1. University of Chicago, Codex Ms. 34 DS ID: DS16671 Title: Commentary on Decretals of Gregory IX Author: Petrus Veronensis Place: Italy Date: 1519.
2. Newberry Library, VAULT folio Case MS 68 DS ID: DS17781 Title: Commentary on Decretals of Gregory IX Place: France Date: between 1425 and 1475