Muestra de maíz recuperada de Trinchera 1A, Nivel 6, en un contexto de la Fase Cuadros (Clark 1994:547, Appendix 3).
Clark, J. E. 1994 The Development of Early Formative Rank Societies in the Soconusco, Chiapas, Mexico. Unpublished Ph.D. dissertation, Department of Department of Anthropology, University of Michigan, Ann Arbor.