APA (7th ed.) Citation

Eppert, F., Gerighausen, J., & Martin, H. (1979). German as it is spoken. Groos.

Chicago Style (17th ed.) Citation

Eppert, Franz, Josef Gerighausen, and Hanno Martin. German as It Is Spoken. Heidelberg: Groos, 1979.

MLA (9th ed.) Citation

Eppert, Franz, et al. German as It Is Spoken. Groos, 1979.