Ellen, R. (1982). Environment, subsistence, and system: The ecology of small-scale social formations. Cambridge University Press.
Cita Chicago (17th ed.)Ellen, Roy. Environment, Subsistence, and System: The Ecology of Small-scale Social Formations. [Cambridge [Cambridgeshire ; New York: Cambridge University Press, 1982.
Cita MLA (9th ed.)Ellen, Roy. Environment, Subsistence, and System: The Ecology of Small-scale Social Formations. Cambridge University Press, 1982.