APA (7th ed.) Citation

Mann, H. K., & Hollnsteiner, J. (1932). The lives of the popes in the early Middle Ages. Kegan.

Chicago Style (17th ed.) Citation

Mann, Horace K., and Johannes Hollnsteiner. The Lives of the Popes in the Early Middle Ages. London: Kegan, 1932.

MLA (9th ed.) Citation

Mann, Horace K., and Johannes Hollnsteiner. The Lives of the Popes in the Early Middle Ages. Kegan, 1932.