Conservation in the United States 
by A.F. Gustafon and others. 
 - 3. ed. 
 - Ithaca, New York  Comstock Publishing Associates  1967. 
 - ix, 534 p.  ill. 
<br/><br/> "Suggestions for supplementary reading": p. 513-520. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Natural resources--U.S.