In the original Cantus index, differentiae were identified by arbitrarily-assigned numbers within each mode. There are two or three different sets of differentiae within this manuscript, indicated by lower-case letters in the "Extra" field, with some from the original layer of the manuscript, which are written without staff lines in the margins of the manuscript, and others notated on small marginal staves.
Downey, Charles. Inventory of Utrecht, Universiteitsbibliotheek, Ms. 406 (shelfmark 3 J 7). In: Cantus: A Database for Latin Ecclesiastical Chant: Inventories of Chant Sources. Directed by Debra Lacoste (2011-), Terence Bailey (1997-2010), and Ruth Steiner (1987-1996). Web developer, Jan Kolácek (2011-).
Images: Antiphonale, UBU Hs. 406 (Hs 3 J 7), Utrecht University
Standardized manuscript tonary completed by Rebecca Shaw (Dalhousie University) on March 11, 2018. Edited by Jennifer Bain, Sister Ilaria Culshaw, and Lucia Denk (Dalhousie University) on July 24, 2019 and Rebecca Shaw on August 7, 2019.