APA (7th ed.) Zitazioa

(2006). Guidelines for soil description (fourth edition.).

Chicago Style (17th ed.) Zitazioa

Guidelines for Soil Description. fourth edition. 2006.

MLA (9th ed.) Zitazioa

Guidelines for Soil Description. fourth edition. 2006.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.