Cita APA (7a ed.)

Knowles, D., & Obolensky, D. (1972). The Christian centuries: 2, The Middle Ages (2nd repr.). Darton, Longman and Todd ; McGraw-Hill Book Company.

Cita Chicago Style (17a ed.)

Knowles, David, y Dimitri Obolensky. The Christian Centuries: 2, The Middle Ages. 2nd repr. London : New York: Darton, Longman and Todd ; McGraw-Hill Book Company, 1972.

Cita MLA (9a ed.)

Knowles, David, y Dimitri Obolensky. The Christian Centuries: 2, The Middle Ages. 2nd repr. Darton, Longman and Todd ; McGraw-Hill Book Company, 1972.