Cita APA (7a ed.)

Orr, E. L., & Orr, W. L. (1996). Geology of the Pacific Northwest. McGraw-Hill.

Cita Chicago Style (17a ed.)

Orr, Elizabeth L., y William L. Orr. Geology of the Pacific Northwest. New York: McGraw-Hill, 1996.

Cita MLA (9a ed.)

Orr, Elizabeth L., y William L. Orr. Geology of the Pacific Northwest. McGraw-Hill, 1996.