Mansfied, George Rogers <br/><br/>
Phosphate Rock in 1922. 

 - Washington, D.C.  Government Printing Office  1923 
 - pp. 109-132 
 - Mineral Resources of the United States, 1923-Part II .
<br/><br/> Impreso 
<br/><br/><br/>Ingles 
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA<br/>FOSFATO
<br/><br/><label>Dewey Class. No.: </label>661