Principles source of information used in the creation of the resources on popes and the papacy:
Lives of the Popes, by Richard P. McBrien
Chronicle of the Popes, by P.G. Maxwell-Stuart
Pope-Pourri, by John Dollison
Encyclopedia of Catholicism, edited by Richard P. McBrien
The Bad Popes, by E.R. Chamberlin
The She-Pope, by Peter Standord.
