Research methods 
Sevilla, Consuelo G. 
 - revised edition. 
 -  Rex Book Store.  1992 
 - xiv, 333 pages 
<br/><br/>
<br/><br/><label>ISBN: </label>9-71231058-2 
<br/><br/><label>Dewey Class. No.: </label>F 001.4 R31 1992