Creswell, John W. <br/><br/>
Research design :  qualitative, quantitative, and mixed methods approaches / 
John W. Creswell. 
 - 4th ed. 
 - Los Angeles :  Sage Publications,  2014. 
 - xxix, 273 p. :  ill. ;  26 cm. 
<br/><br/> Includes Index. 
<br/><br/>Includes bibliographical references. 
<br/><br/><label>ISBN: </label>9781412965576 (pbk. ) 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Social sciences--Research--Methodology.<br/>Social sciences--Statistical methods.