Παραπομπή APA

Giller,Ken E, & wilson,kate j. (1991). Nitrogen fixation in tropical croping systems. CAB international.

Παραπομπή Chicago Style

Giller,Ken E, και wilson,kate j. Nitrogen Fixation in Tropical Croping Systems. United Kingdom: CAB international, 1991.

Παραπομπή MLA

Giller,Ken E, και wilson,kate j. Nitrogen Fixation in Tropical Croping Systems. CAB international, 1991.