Cohen, Louis And Manion, Lawrence <br/><br/>
Research Methods in Education 

 - 4th Ed 
 - Routledge, London  1980 
 - xxi, 414 
<br/><br/><label>ISBN: </label>0-415-10235-9 
<br/><br/><label>Dewey Class. No.: </label>370.78 Coh /Man