Millon, Henry A.; Bloch, Raymond; Boardman, John; Bush-Brown, Albert; Cannon-Brookes, Peter; Culican, William; Middleton, Robin David; Fleming, William; Martindale, Andrew Henry Robert; Hoffmann, Herbert; Kemp, Martin J.; Watkin, David John; Timmers, Jan Joseph Marie; Scranton, Robert L.; Millikin, Sandra; Coffin, David R.; Morrison, Hugh Sinclair; Stern, Henri; Rice, David Talbot; Voyce, Arthur; Zukowsky, John. 12. siječnja 2000. Roman And Early Christian. Encyclopedia Britannica. Encyclopædia Britannica, Inc. Pristupljeno 30. lipnja 2019.