Citazione Stile APA (7a Edizione)

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

Citazione stile Chigago Style (17a edizione)

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

Citatione MLA (9a ed.)

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