found: Piacenza, Biblioteca capitolare 65, c1993.
found: Il libro del maestro, 1997:commentary vol. t.p. (Liber magistri) commentary vol. introd. (original text in English by B.M. Jensen, p. 129-130: manuscript titles used most often by modern scholars are Liber magistri and Codice magno; musicologists seem to prefer Liber officiorum; also used is Pia 65, an abbreviation for the repository designation; author cites (p. 130) medieval sources which refer to Pia 65 as Liber magistri)
found: New Grove dict., 2nd ed.(Under Piacenza: Liber magistri (I-PCd 65); under Sources, MS, II, 5: Western plainchant, 12th century: Piacenza, Duomo, Biblioteca e archivio capitolare, 65. "Liber officiorum" or "Liber magistri")
found: MGG, 2nd. ed.(under Piacenza: Codice magno, also known as Liber magistri (I-PCd, 65))