Substitution Relationships, Resource Requirements and Income Variability in the utilization of for rage crops. 

 - U.S.  Bureau of Agriculture Economics         1952 
 - 868-938p.  cm. 
 - Research Bulletin 390 .
<br/><br/><label>Source: </label> General Book 
<br/><br/><label>Dewey Class. No.: </label>X9(J):9.73.N52, J2