1. Kroeber, A. L. and Kluckhohn. 1952.Culture: A Critical Review of Concepts and Definitions, Vol. XLVII, 153–154. Cambridge, Mass.: Papers of the Peabody Museum of American Archeology and Ethnology, Harvard University. No. 1,
2. The Urban Revolution
3. Viking Fund Publications in Anthropology, No. 32;Braidwood Robert J.,1962