Principles of resources conservation policy ; with some applications to soil and water resources 

 - Washington :  NAS,  1961 
 - 50 p.  ; gráfs. 
 - NAS. Publication  ; 885 .
 - NAS. Publication  ; 885 .
<br/><br/><label>LCCN: </label>30208 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Recursos naturales--Conservación.