Zürich, Zentralbibliothek, Rh. 42
Selected Canon Law Collections, ca. 500–1234
Zürich, Zentralbibliothek, Rh. 42 is a commentary on Gratian. As already Mordek, Review of Melnikas p. 410 pointed out, the reference in Melnikas vol. 3 p. 1266 on "Rheinau, Klosterbibliothek, 133" may actually refer to Zürich, Zentralbibliothek, Rh. 42. In any case, it is not a copy of Gratian.