Παραπομπή σε μορφή APA (7η εκδ.)

Cheetham, N. (1982). Keepers of the keys: A history of the popes from St. Peter to John Paul ll. Charles Scribner's.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Cheetham, Nicholas. Keepers of the Keys: A History of the Popes from St. Peter to John Paul Ll. New York: Charles Scribner's, 1982.

Παραπομπή σε μορφή MLA (9th εκδ.)

Cheetham, Nicholas. Keepers of the Keys: A History of the Popes from St. Peter to John Paul Ll. Charles Scribner's, 1982.