Brand, Charles M. (1968). Byzantium Confronts the West, 1180–1204. Cambridge, Massachusetts: Harvard University Press. LCCN 67-20872. OCLC 795121713.
Brand, Charles M. (1968). Byzantium Confronts the West, 1180–1204. Cambridge, Massachusetts: Harvard University Press. LCCN 67-20872. OCLC 795121713.