Originally published, New York: Simon and Schuster, 1969.
Bibliographyp.307-310. _ Includes index.
The three Popes : an account of the great schism - when rival Popes in Rome, Avignon and Pisa vied for the rule of Christendom by Marzieh Gail. ISBN 0709128207. Published by Hale in 1972. Publication and catalogue information, links to buy online and reader comments.