APA (7th ed.) Citation

Willis, G. G. (1994). A history of early Roman liturgy to the death of Pope Gregory the Great. Subsidia.

Chicago Style (17th ed.) Citation

Willis, Geoffrey Grimshaw. "A History of Early Roman Liturgy to the Death of Pope Gregory the Great." Subsidia 1994.

MLA (8th ed.) Citation

Willis, Geoffrey Grimshaw. "A History of Early Roman Liturgy to the Death of Pope Gregory the Great." Subsidia, 1994.

Warning: These citations may not always be 100% accurate.