Spedding, C. R. W. <br/><br/>
Biological efficiency in agriculture 
C.R.W. Spedding, J.M. Walsingham, and A.M. Hoxey 
 - London  New York  Academic Press  1981 
 - x, 383 p.  ill.  23 cm 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Agricultural productivity<br/>Biological productivity<br/>Agriculture<br/>Biology, Economic
<br/><br/><label>Dewey Class. No.: </label>630