Witte, R. S. (1985). Statistics (2nd ed.). Holt, Rinehart.
Lua i Stíl Chicago (17ú heag.)Witte, Robert S. Statistics. 2nd ed. New York: Holt, Rinehart, 1985.
Lua MLA (9ú heag.)Witte, Robert S. Statistics. 2nd ed. Holt, Rinehart, 1985.
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