@article {,
	title = {Towards a More Comprehensive Model of Interregional Commodity Distribution: Political Variables and Prehistoric Obsidian Procurement in Mesoamerica},
	journal = {American Antiquity},
	volume = {47},
	number = {2},
	year = {1982},
	pages = {260-275},
	author = {Zeitlin, Robert N.}
}