APA

Thomas M. Z., Schramm U. & Brommer E. (1960). Alexander von Humboldt : scientist, explorer, adventurer. New York: Pantheon Books.

Chicago

Thomas M Z, Schramm Ulrik and Brommer Elizabeth. 1960. Alexander von Humboldt : scientist, explorer, adventurer. New York: Pantheon Books.

Harvard

Thomas M. Z., Schramm U. and Brommer E. (1960). Alexander von Humboldt : scientist, explorer, adventurer. New York: Pantheon Books.

MLA

Thomas M Z, Schramm Ulrik and Brommer Elizabeth. Alexander von Humboldt : scientist, explorer, adventurer. New York: Pantheon Books. 1960.