@book{481,
	author = {Kalbermatten J M, Julius D S, Gunnerson C.G.},
	title = {A summary of technical and economic options.},
	publisher = {World Bank,},
	year = {1980.},
	series = {(Appropriate technology for water supply and sanitation ; v. 1-A)},
	address = {Washington, D.C. : }
}