Birkeland, P. W. (1999). Soil and geomorphology. U.pr..
Chicago Style (17th ed.) CitationBirkeland, Peter W. Soil and Geomorphology. Oxford: U.pr., 1999.
MLA (9th ed.) CitationBirkeland, Peter W. Soil and Geomorphology. U.pr., 1999.
Advarsel: Disse citationer er muligvist ikke 100% nøjagtige.