Selltiz, C., Wrightsman, L. S., & Cook, S. W. (1976). Research methods in social relations (3rd ed.). Holt, Rinehart and Winston.
Lua i Stíl Chicago (17ú heag.)Selltiz, Claire, Lawrence S. Wrightsman, agus Stuart Wellford Cook. Research Methods in Social Relations. 3rd ed. New York: Holt, Rinehart and Winston, 1976.
Lua MLA (9ú heag.)Selltiz, Claire, et al. Research Methods in Social Relations. 3rd ed. Holt, Rinehart and Winston, 1976.
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