Gaya APA

Swanson, C, P., Starhler, A, N. (1972). Planet earth its physical systems through geologic time . New York: New York: Harper & Row; 1972.

Gaya MLA

Swanson, Carl, P.., Starhler, Arthur, N. "Planet earth its physical systems through geologic time". New York: New York: Harper & Row; 1972, 1972. Text.