Barr, Cyrilla. 1988. The Monophonic Lauda and the Lay Religious Confraternities of Tuscany and Umbria in the Late Middle Ages. Medieval Institute Publications.  Kalamazoo, Michigan.

Barr, Cyrilla. 1978. Lauda singing and the tradition of the disciplinati. Mandato: A reconstruction of two texts of the office of tenebrae. L'Ars nova italiana del Trecento IV: Certaldo 1975, 21-44.