APA (7th ed.) Zitazioa

SOPHER, C. D. Soils and soil management. (2nd ed.). c1980.

Chicago Style (17th ed.) Zitazioa

SOPHER, Charles D. Soils and Soil Management. 2nd ed. Virgi-nia: c1980.

MLA (9th ed.) Zitazioa

SOPHER, Charles D. Soils and Soil Management. 2nd ed. c1980.