Παραπομπή APA

Kummel, B. (1961). History of the earth: :introduction to histrocal geology. Eurasia publishing.

Παραπομπή Chicago Style

Kummel, Bernhard. History of the Earth: :introduction to Histrocal Geology. New delhi: Eurasia publishing, 1961.

Παραπομπή MLA

Kummel, Bernhard. History of the Earth: :introduction to Histrocal Geology. Eurasia publishing, 1961.