Zentall, T R <br/><br/>
Key pecking in pigeons produced by pairing keylight with inaccessible grain.  [electronic resource] 

 -  Journal of the experimental analysis of behavior  Mar 1975 
 - 199-206 p.  digital 
<br/><br/> Publication Type: Journal Article 
<br/><br/><label>ISSN: </label>0022-5002 
<br/><br/><label>Standard No.: </label>10.1901/jeab.1975.23-199  doi