See Iter liturgicum italicum, neumatic notation. ff.1r-v has computus diagram, ff.2r-8v has calendar, See Bannister, H. M. Monumenti vaticani di paleografia musicale latina ID# 643[ Title: Breviarium, Folio: 300v, 301r, Century: 1443, Source: italiano, Provinance: Milano (humilitati), Lombardia, Notation: quadrata]