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Origin of the former north american ice sheet. 

 - New York-US :   Geografical record,   1943. 
 - páginas 479-481 :   Ilustraciones blanco y negro 
 - Irregular 
 - Vol. XXXIII, no. 3(Jul. 1943) 
 - The Geographical Review ;   no. 3 .
 - The Geographical Review. .