Cita APA (7a ed.)

Emmons, W. H. (1940). The principles of economic geology. McGraw Hill.

Cita Chicago Style (17a ed.)

Emmons, William Harvey. The Principles of Economic Geology. New York: McGraw Hill, 1940.

Cita MLA (8a ed.)

Emmons, William Harvey. The Principles of Economic Geology. McGraw Hill, 1940.