Popham, W. J., & Sirotnik, K. A. (1973). Educational statistics: Use and interpretation (2nd ed.). Harper and Row.
Lua i Stíl Chicago (17ú heag.)Popham, W. James, agus Kenneth A. Sirotnik. Educational Statistics: Use and Interpretation. 2nd ed. New York: Harper and Row, 1973.
Lua MLA (9ú heag.)Popham, W. James, agus Kenneth A. Sirotnik. Educational Statistics: Use and Interpretation. 2nd ed. Harper and Row, 1973.
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