00000cam a22000003a 4500 UP-8027390931313939218 Buklod 20150729113714.0 m |o d | ta 150729s1986 xx d r |||| u| 0566005107 (iLib)UPVIS-00038156045 VML/jcs. 7-29-15 eng HM 261 B34 1986 Belson, William A. Validity in survey research with special reference to the techniques of intensive interviewing and the progressive modification for testing and constructing difficult or sensitive measures for use in survey research a report by William A. Belson. England Gower c1986. 565 p. Public opinion polls -- evaluation. public opinion -- Great Britain. Social sciences -- Methodology. UPVIS UPV-ML HM 261 B34 1986 Book