1. Adams, R.E.W. (1986). Rio Azul: Lost city of the Maya.National Geographic, 169 420?451.
2. Adams, R.M. (1955). Developmental stages in ancient Mesopotamia. In J.H. Steward (Ed.),Irrigation civilizations: a comparative study (pp. 6?18). Washington DC: Pan American Union.
3. Allan, W. (1972). Ecology, techniques and settlement patterns. In P.J. Ucko, R. Tringham, & G.W. Dimbleby (Eds.),Man, settlement and urbanism (pp. 211?26). London: Duckworth.
4. Bacon, E. (1971).Archaeology: discoveries in the 1960s. London: Cassell.
5. Bartlett, H.H. (1956). Fire, primitive agriculture, and grazing in the tropics. In W.L. Thomas, Jr. (Ed.),Man's role in changing the face of the earth (pp. 692?720). Chicago: University of Chicago Press.