Butterfield, H. S. (1960). International conflict in the twentieth century: A Christian view. Greenwood Press.
Dyfyniad Arddull ChicagoButterfield, Herbert Sir. International Conflict in the Twentieth Century: A Christian View. New York: Greenwood Press, 1960.
Dyfyniad MLAButterfield, Herbert Sir. International Conflict in the Twentieth Century: A Christian View. Greenwood Press, 1960.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.