APA (7e ed.) Bronvermelding

Ludman, A., & Coch, N. K. (1982). Physical geology. McGraw-Hill.

Chicago (17e ed.) Bronvermelding

Ludman, Allan, en Nicholas K. Coch. Physical Geology. New York: McGraw-Hill, 1982.

MLA (9e ed.) Bronvermelding

Ludman, Allan, en Nicholas K. Coch. Physical Geology. McGraw-Hill, 1982.