Sampling and Choosing Cases in Qualitative Research/  a realist approach 
Emmel,Nick 
 - 1 
 - Los angeles:  SAGE Publications Ltd,  2013. 
 - 172 
<br/><br/><label>ISBN: </label>0857025104 
<br/><br/><label>Dewey Class. No.: </label>300.72  / EMM/S