Gaya APA

Christopherson, R, W. (2014). PEARSON NEW INTERNATIONAL EDITION: Geosystems An Introduction to Physical Geography Eight Edition . : Pearson Education Limited.

Gaya MLA

Christopherson, Robert, W.. "PEARSON NEW INTERNATIONAL EDITION: Geosystems An Introduction to Physical Geography Eight Edition". : Pearson Education Limited, 2014. Buku.