"Sergius at once declared the ordinations conferred by Formosus null; but that he put his two predecessors to death, and by illicit relations with Marozia had a son, who was afterwards John XI, must be regarded as highly doubtful. These assertions are only made by bitter or ill-informed adversaries, and are inconsistent with what is said of him by respectable contemporaries [such as Flodoard]." Mann, Horace Kinder (1912), “Sergius III”, 《가톨릭 백과사전》 (New York: Robert Appleton Company) XIII, 2008년 1월 6일에 확인함
