APA-referens (7:e uppl.)
Clewlow, W. C. (1967). Colossal heads of the Olmec culture. University of California Archaeological Research Facility.
Chicago-referens (17:e uppl.)
Clewlow, William C. Colossal Heads of the Olmec Culture. Berkeley: University of California Archaeological Research Facility, 1967.
MLA-referens (9:e uppl.)
Clewlow, William C. Colossal Heads of the Olmec Culture. University of California Archaeological Research Facility, 1967.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.