Ullmann, W. (1972). A short history of the papacy in the Middle Ages. Methuen & Co.
芝加哥风格引文Ullmann, Walter. A Short History of the Papacy in the Middle Ages. [London]: Methuen & Co, 1972.
MLA引文Ullmann, Walter. A Short History of the Papacy in the Middle Ages. Methuen & Co, 1972.
警告：这些引文格式不一定是100％准确.