COHEN, Louis <br/><br/>
Research methods in education 
/Louis Cohen, Lawrence Manion and Keith Morrison. 
 - 6th  
 - London;  Routledge:  2007. 
 - xviii, 638 p. :   ill. ;   26 cm. 
<br/><br/> Includes bibliographical references and index 
<br/><br/><label>ISBN: </label>9780415374101 
<br/><br/><label>LC Class. No.: </label>LB1028 C572