Wherry, Edgar T. <br/><br/>
United States Geological Survey Bulletin ;   no.580-H 

 - Washington-US :   United States Geological Survey Bulletin,   1914. 
 - páginas 147-151 :   IIustraciones blanco y negro 
 - No. 580-H (1914) 
 - United States Geological Survey Bulletin ;   no.580-H .
 - United States Geological Survey. .