Ancient america :   Dating sloth-eating culture. 

 - Nuevo Mexico-US :   School of american research ,   1938. 
 - páginas 162-163 :   Ilustraciones blanco y negro 
 - Irregular 
 - Vol.XLIV, no.22-24 (Jun.1938) 
 - El palacio ;   no.22-24 .
 - University of New Mexico. .