In introduction to historical plant geography. 

 - New York-US :   Geografical record,   1944. 
 - páginas 688-689 :   Ilustraciones blanco y negro 
 - Irregular 
 - Vol. XXXIV, no. 4(Oct. 1944) 
 - The Geographical Review ;   no. 4 .
 - The Geographical Review. .