Petrobelli, Pierluigi. 1968. Some Dates for Bartolino da Padova. Studies in Music History: Essays for Oliver Strunk, edited by Pierluigi Petrobelli, 85-112. Princeton: Princeton University Press.

Pirrotta, Nino. 1968. Church Polyphony Apropos of a New Fragment at Foligno. Studies in Music History: Essays for Oliver Strunk, edited by Nino Pirrotta, 113-26. Princeton: Princeton University Press.