Gallup, G. H. (1944). A guide to public opinion polls. Princeton University Press.
Lua i Stíl Chicago (17ú heag.)Gallup, George Horace. A Guide to Public Opinion Polls. Princeton: Princeton University Press, 1944.
Lua MLA (9ú heag.)Gallup, George Horace. A Guide to Public Opinion Polls. Princeton University Press, 1944.
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