Cita APA (7a ed.)

Birkeland, P. W. (1999). Soil and geomorphology. U.pr..

Cita Chicago Style (17a ed.)

Birkeland, Peter W. Soil and Geomorphology. Oxford: U.pr., 1999.

Cita MLA (9a ed.)

Birkeland, Peter W. Soil and Geomorphology. U.pr., 1999.