Welch, S., & Comer, J. (1975). Public opinion: Its formation, measurement, and impact. Mayfield.
Lua i Stíl Chicago (17ú heag.)Welch, Susan, agus John Comer. Public Opinion: Its Formation, Measurement, and Impact. Palo Alto, Calif: Mayfield, 1975.
Lua MLA (9ú heag.)Welch, Susan, agus John Comer. Public Opinion: Its Formation, Measurement, and Impact. Mayfield, 1975.
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