Encyclopedia Britannica Online (2002-2014) "Andean civilization; The pre-Inca periods; The Early Intermediate period; The southern coast; pre-Columbian civilizations," accessed 17 February 2009
Encyclopedia Britannica Online (2002-2014) "Andean civilization; The pre-Inca periods; The Early Intermediate period; The southern coast; pre-Columbian civilizations," accessed 17 February 2009