Nickles, John. <br/><br/>
United States Geological Survey Bulletin ;   no.584 

 - Washington-US :   United States Geological Survey Bulletin,   1914. 
 - páginas 5-183 :   IIustraciones blanco y negro 
 - No. 584 (1914) 
 - United States Geological Survey Bulletin ;   no.584 .
 - United States Geological Survey. .