Methods and techniques of research 
Sanchez, Custodiosa Ancheta. 
 - third edition. 
 -  Rex Book Store.  1998 
 - xi, 263 pages. 
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<br/><br/><label>ISBN: </label>9-71232301-3 
<br/><br/><label>Dewey Class. No.: </label>F 001.4 Sa5m 1998