Otis Smith, George. <br/><br/>
United States Geological Survey Bulletin ;   no.599 

 - Washington-US :   United States Geological Survey Bulletin,   1914. 
 - páginas 3-111 :   IIustraciones blanco y negro 
 - No. 599 (1914) 
 - United States Geological Survey Bulletin ;   no.599 .
 - United States Geological Survey. .