APA استشهاد

Christopherson, R. W. (2006). Geosystems: An introduction to physical geography (6th ed.). Pearson.

استشهاد بنمط شيكاغو

Christopherson, Robert W. Geosystems: An Introduction to Physical Geography. 6th ed. New Jersey: Pearson, 2006.

MLA استشهاد

Christopherson, Robert W. Geosystems: An Introduction to Physical Geography. 6th ed. Pearson, 2006.