Stephens, David W,  1955 <br/><br/>
Foraging theory / 
David W. Stephens and John R. Krebs 
 - Princeton, N. J. :  Princeton University Press,  1986 
 - 247 p.  ;  24 cm. 
<br/><br/>Bibliographical references and index 
<br/><br/><label>ISBN: </label>0691084424