In the original Cantus index for this manuscript, the differentiae were identified using a two-digit system: a letter to indicate the last note of the differentia and a number to distinguish between differentiae in the same mode with the same last note.
Helsen, Kate. Inventory of Fulda, Hessische Landesbibliothek, Aa 55. Edited by Andrew Mitchell. 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, 100 Aa 55, Fulda University and State Library
Standardized manuscript tonary completed by Rebecca Shaw (Dalhousie University) on October 9, 2018. Edited by Jennifer Bain, Sister Ilaria Culshaw, Andrea Klassen, and Brayden Olson and (Dalhousie University) on August 8, 2019 and Rebecca Shaw on August 11, 2019.