APA (7th ed.) Citation

Ackermann, P., Krimmel, B., & Krimmel, E. (1980). Peter Ackermann.

Chicago Style (17th ed.) Citation

Ackermann, Peter, Bernd Krimmel, and Elisabeth Krimmel. Peter Ackermann. Darmstadt, 1980.

MLA (8th ed.) Citation

Ackermann, Peter, et al. Peter Ackermann. 1980.