Blackwell, H R <br/><br/>
Psychological thresholds / 
by H R Blackwell 
 - University of Michigan :  Engineering Reserach Institute,   1953. 
 - 227p. : 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Psychology
<br/><br/><label>Dewey Class. No.: </label>150  / BLA.P