@book {,
	title = {Obsidian distribution and provenience in the central highlands and coast of Peru during the Preceramic Period},
	series = {Contributions to the University of California Archaeology Research Facility},
	volume = {36},
	year = {1978},
	note = {Andes Geog},
	pages = {61-83},
	publisher = {University of California},
	organization = {University of California},
	address = {Berkeley, pp. 61-83.},
	author = {Richard L. Burger and Asaro, Frank}
}