APA (7th ed.) Citation

Sharer, R. J., & Sheets, P. D. (1978). The Prehistory of Chalchuapa, El Salvador. University of Pennsylvania Press.

Chicago Style (17th ed.) Citation

Sharer, Robert J., and Payson D. Sheets. The Prehistory of Chalchuapa, El Salvador. Philadelphia: University of Pennsylvania Press, 1978.

MLA (8th ed.) Citation

Sharer, Robert J., and Payson D. Sheets. The Prehistory of Chalchuapa, El Salvador. University of Pennsylvania Press, 1978.