1. McDonald Andrew J. 1971 Tzutzuculi, a Preclassic site of coastal Chiapas. Unpublished M.A. thesis, Department of Anthropology, University of the Americas. 1974 Middle Preclassic ceremonial centers in southern Chiapas. Paper presented at the 41st meeting of the International Congress of Americanists, Mexico, D.F.
2. El sistema Prehispanico de comunicaciones entre Chiapas y Tabasco;Navarrete;Anales de Antropologia,1973
3. Navarrete Carlos 1971 Algunas piezas Olmecas de Chiapas y Guatemala. Anales de Antropologia 8:69–82.
4. Navarrete Carlos 1959 A brief reconnaissance in the region of Tonala, Chiapas, Mexico. New World Archaeological Foundation, Papers 3.