Hughes, Harold De Mott. <br/><br/>
Crop production / 
Harold D. Hughes, Darrel S. Metcalfe. 
 - 3d ed. 
 - New York :  Macmillan,  1972. 
 - xi, 627 p. :  ill. 
<br/><br/>Includes bibliographies. 
<br/><br/><label>LCCN: </label>75146619 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Field crops.