Simmonds, N. W. <br/><br/>
Principles of crop improvement / 
N. W. Simmonds. 
 - Harlow :  Longman Group Ltd,  1979. 
 - xiii, 408 p. :  plates ;  22 cm. 
<br/><br/>Includes index and bibliography. 
<br/><br/> Open access. 
<br/><br/><label>ISBN: </label>0582407370 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Crops.<br/>Cropping systems.