APA (7th ed.) Citation

Einhard, a. 7., Notker, B., & Ganz, D. (2008). Two lives of Charlemagne. Penguin.

Chicago Style (17th ed.) Citation

Einhard, approximately 770-840, Balbulus Notker, and David Ganz. Two Lives of Charlemagne. London ; New York: Penguin, 2008.

MLA (8th ed.) Citation

Einhard, approximately 770-840, et al. Two Lives of Charlemagne. Penguin, 2008.