Arellano, A. R. V. <br/><br/>
Cambrian stratigraphy and paleontology near caborca, northwestern sonora, México 

 - Washington, D. C :   Smithsonian Institution,   1952. 
 - vi, 184 p. :   láms. ;   21 cm. 
<br/><br/> Smithsonian Miscellaneous Collections, vol. 119, Nº 1. Charles D. And Mary Vaux Walcott Research Fund