Thilakarathna , HE , MU සමාජීය විද්යාවන්හි ක්රමවේදය - Colombo : Rathna , 2001 . - 158 P . ; 21cm ISBN: 9555694370 Subjects--Topical Terms: Methodology of Social Sciences Subjects--Index Terms: Research methodologymethodology Dewey Class. No.: 001.4