Joint meeting of A.A.A.S. and A.A.G. at philadelphia. 

 - New York-US :   Geografical record,   1941. 
 - páginas 318-319 :   Ilustraciones blanco y negro 
 - Irregular 
 - Vol. XXXI, no. 2(Apr. 1941) 
 - The Geographical Review ;   no. 2 .
 - The Geographical Review. .