A systems approach to conservation tillage  
/ edited by Frank M. D'Itri 
 - Chelsea:  Lewis Publishers  , 1985 
 - 384 p.:  il.,  23 cm. 
<br/><br/><label>ISBN: </label>0-87371-024-X 
<br/><br/><label>Subjects--Index Terms: </label>Labranza de conservación