Reina, Ruben R.. <br/><br/>
The ritual of the skull in peten, Guatemala. 

 - Pennsilvania-US :   Univesity of Pennsylvania,   1962. 
 - páginas 27-36 :   ilustraciones blanco y negro 
 - Trimenstral 
 - Vol.4, no 4(1962)  
 - Expedition. the bulletin of the university museum of the university of pennsilvania ;   no. 4 .
 - University of Pennsylvania. .