APA (7th ed.) Citation

Cicero, M. T., Griffin, M. T., & Atkins, E. M. (2011). On duties. Cambridge University Press.

Chicago Style (17th ed.) Citation

Cicero, Marcus Tullius, Miriam T. Griffin, and E. M. Atkins. On Duties. Cambridge [England] ; New York: Cambridge University Press, 2011.

MLA (9th ed.) Citation

Cicero, Marcus Tullius, et al. On Duties. Cambridge University Press, 2011.