Creswell, John W.  <br/><br/>
Research design:   qualitative, quantitative and mixed methods approaches / 
John W. Creswell 
 - Thousand Oaks, Calif. :  Sage Publications,,   2009 
 - Xxix, 260 p. ;   26 cm. 
<br/><br/><label>ISBN: </label>9781452274614 
<br/><br/><label>LC Class. No.: </label>H62.C6963 R2009