Stanish, Charles; Burger, Richard L.; Cipolla, Lisa M.; Glascock, Michael D.; Quelima, Esteban (December 2002). "Evidence for Early Long-Distance Obsidian Exchange and Watercraft Use from the Southern Lake Titicaca Basin of Bolivia and Peru". Latin American Antiquity. 13 (4): 444–54. doi:10.2307/972225. JSTOR972225.
Stanish, Charles; Burger, Richard L.; Cipolla, Lisa M.; Glascock, Michael D.; Quelima, Esteban (December 2002). "Evidence for Early Long-Distance Obsidian Exchange and Watercraft Use from the Southern Lake Titicaca Basin of Bolivia and Peru". Latin American Antiquity. 13 (4): 444–54. doi:10.2307/972225. JSTOR972225.