Cita APA (7a ed.)

Kummel, B. (1970). History of the earth: An introduction to historical geology (2a ed.). Freeman and Company.

Cita Chicago Style (17a ed.)

Kummel, Bernhard. History of the Earth: An Introduction to Historical Geology. 2a ed. San Francisco: Freeman and Company, 1970.

Cita MLA (8a ed.)

Kummel, Bernhard. History of the Earth: An Introduction to Historical Geology. 2a ed. Freeman and Company, 1970.