Orr, E. L. (1996). Geology of the Pacific Northwest. McGraw-Hill.
Cita Chicago (17th ed.)Orr, Elizabeth L. Geology of the Pacific Northwest. New York: McGraw-Hill, 1996.
Cita MLA (9th ed.)Orr, Elizabeth L. Geology of the Pacific Northwest. McGraw-Hill, 1996.
Atenció: Aquestes cites poden no estar 100% correctes.