1. Progress report on the 1960-1964 field seasons, National Geographic Society-Tulane University Dzibilchaltun program;Blalock;Tulane University, Middle American Research Institute, Publication,1965
2. Scholes Francis V. , and Roys Ralph L. 1948 The Maya Chontal Indians of Acalan- Tixchel: a contribution to the history and ethnography of the Yucatan peninsula. Carnegie Institution of Washington, Publication 560.
3. Webster David L. 1972 The fortifications of Becan, Campeche, Mexico. Ph.D. dissertation, University of Minnesota.
4. Lowland Maya native society at Spanish contact;Roys;Handbook of Middle American Indians,1965