APA Citation

Christopherson, R. W., & Birkeland, G. Geosystems: An introduction to physical geography (Ninth edition.).

Chicago Style Citation

Christopherson, Robert W., and Ginger Birkeland. Geosystems: An Introduction to Physical Geography. Ninth edition.

MLA Citation

Christopherson, Robert W., and Ginger Birkeland. Geosystems: An Introduction to Physical Geography. Ninth edition.

Warning: These citations may not always be 100% accurate.