Belson, William A.
Validity in survey research - Emgland Gower 1986 - xviii, 565 p.
566005107
Public - opinion polls - evaluation
303.38072 / BEL
Validity in survey research - Emgland Gower 1986 - xviii, 565 p.
566005107
Public - opinion polls - evaluation
303.38072 / BEL