Cottrell, K.W. <br/><br/>
Gypsum in 1921. 

 - Washington, D.C.  Government Printing Office  1922 
 - pp. 89-96 
 - Mineral Resources of the United States, 1921-Part II .
<br/><br/> Impreso 
<br/><br/><br/>Ingles 
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA<br/>YESO
<br/><br/><label>Dewey Class. No.: </label>661