Παραπομπή APA

DOUGLAS, M., & NORMAN, D. (2007). FARMING SYSTEMS DEVELOPMENT AND SOIL CONSERVATION.

Παραπομπή Chicago Style

DOUGLAS, MALCOLM, και DAVID NORMAN. FARMING SYSTEMS DEVELOPMENT AND SOIL CONSERVATION. DELHI, DAYA PUBLISHING HOUSE, 2007.

Παραπομπή MLA

DOUGLAS, MALCOLM, και DAVID NORMAN. FARMING SYSTEMS DEVELOPMENT AND SOIL CONSERVATION. 2007.