@article {,
	title = {Aboriginal Trephining in Bolivia},
	journal = {American Anthropologist},
	volume = {6},
	number = {4},
	year = {1904},
	note = {obsidian called chillisaa kala or "black flint", while "llisa" means "white flint". Obsidian, where available, was probably used trephining (p446). Also quotes Cobo on stomach operations using obsidian.},
	pages = {440-446},
	author = {Bandelier, Adolph F.}
}