APA (7th ed.) Citation

Gasser, M., & Killer, P. (1970). Alexander von Humboldt. Conzett & Huber.

Chicago Style (17th ed.) Citation

Gasser, Manuel, and Peter Killer. Alexander Von Humboldt. Zürich: Conzett & Huber, 1970.

MLA (8th ed.) Citation

Gasser, Manuel, and Peter Killer. Alexander Von Humboldt. Conzett & Huber, 1970.

Warning: These citations may not always be 100% accurate.