Conservation of natural resources / 
editor: Guy-Harold Smith; contributors: Robert M. Basile ... [et al.]. 
 - 4th ed. 
 - New York :  Wiley,  1971. 
 - xiii, 685 p. :  ill., maps. 
<br/><br/><label>ISBN: </label>0471801925 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Conservation of natural resources--United States.
<br/><br/><label>Subjects--Geographic Terms: </label><br/>United States--Economic conditions.