GREENWOOD, N., & EDWARDS, J. (1979). Human environments and natural systems. -- 2nd ed. Duxbury Press.
Lua i Stíl Chicago (17ú heag.)GREENWOOD, N.H, agus J.M.B EDWARDS. Human Environments and Natural Systems. -- 2nd Ed. North Scituate: Duxbury Press, 1979.
Lua MLA (9ú heag.)GREENWOOD, N.H, agus J.M.B EDWARDS. Human Environments and Natural Systems. -- 2nd Ed. Duxbury Press, 1979.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.