Kay, R. F., Madden, R. H., Mazzoni, M., Vucetich, M. G., Re, G., Heizler, M., & Sandeman, H. (1999). The oldest Argentine primates: first age determinations for the Colhuehuapian South American Land Mammal 'Age'. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, 166–166.

Kay, R. F., R. H. Madden, M. Mazzoni, M. G. Vucetich, G. Re, M. Heizler, and H. Sandeman. “The oldest Argentine primates: first age determinations for the Colhuehuapian South American Land Mammal 'Age'.” AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, January 1, 1999, 166–166.

Kay RF, Madden RH, Mazzoni M, Vucetich MG, Re G, Heizler M, et al. The oldest Argentine primates: first age determinations for the Colhuehuapian South American Land Mammal 'Age'. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY. 1999 Jan 1;166–166.

Kay, R. F., et al. “The oldest Argentine primates: first age determinations for the Colhuehuapian South American Land Mammal 'Age'.” AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, WILEY-LISS, Jan. 1999, pp. 166–166.

Kay RF, Madden RH, Mazzoni M, Vucetich MG, Re G, Heizler M, Sandeman H. The oldest Argentine primates: first age determinations for the Colhuehuapian South American Land Mammal 'Age'. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY. WILEY-LISS; 1999 Jan 1;166–166.