APA

Mommsen T., Benson R. L. & Morrison K. F. (2000). Imperial lives and letters of the eleventh century. New York: Columbia University Press.

Chicago

Mommsen Theodor, Benson Robert Louis and Morrison Karl Frederick. 2000. Imperial lives and letters of the eleventh century. New York: Columbia University Press.

Harvard

Mommsen T., Benson R. L. and Morrison K. F. (2000). Imperial lives and letters of the eleventh century. New York: Columbia University Press.

MLA

Mommsen Theodor, Benson Robert Louis and Morrison Karl Frederick. Imperial lives and letters of the eleventh century. New York: Columbia University Press. 2000.