Gaya APA

Edwards, N, ., G, -, J. (1979). human environments and natural systems (2). Boston, Massachusetts - USA: Duxbury Press.

Gaya MLA

Edwards, N.J, ., Greenwood, -, JMB. "human environments and natural systems". 2 Boston, Massachusetts - USA: Duxbury Press, 1979. Agroteknologi.