Gaya APA

Swanson, C, P., Fagan, B, M. (NULL). People of the earth an introduction to world prehistory . New: New York: HarperCollins Publishers; 1992.

Gaya MLA

Swanson, Carl, P.., Fagan, Brian, M. "People of the earth an introduction to world prehistory". New: New York: HarperCollins Publishers; 1992, NULL. Text.