APA-referens (7:e uppl.)
Spence, M. W. (1971). Some lithic assemblages of western Zacatecas and Durango, México. University Museum, Southern Illinois University.
Chicago-referens (17:e uppl.)
Spence, Michael W. Some Lithic Assemblages of Western Zacatecas and Durango, México. Carbondale, Illinois: University Museum, Southern Illinois University, 1971.
MLA-referens (9:e uppl.)
Spence, Michael W. Some Lithic Assemblages of Western Zacatecas and Durango, México. University Museum, Southern Illinois University, 1971.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.