J. Combarieu: Étude de philologie musicale. Théorie du rhythme, etc. (1896).
G. L. Houdard: L'Art dit grégorien d'après la notation neumatique (1897).
In Italian
Cardinal G. Bona: De divina psalmodia (1653, new ed. 1747).
F. Magani: L'anticaliturgia romana (1897-99).
Guido Gasperini: Storia della semiografia musicale (1905).
LITERATURE FOR CHAPTER VI
In English
H. E. Wooldridge: Early English Harmony from the 10th to the 15th Century (1897).
John Stainer: Early Bodleian Music: Dufay and his contemporaries (Oxford, 1909).