Keller, G., & Warrack, B. (1994). Essentials of business statistics (2nd ed.). Duxbury Press.
Lua i Stíl Chicago (17ú heag.)Keller, Gerald, agus Brian Warrack. Essentials of Business Statistics. 2nd ed. Belmont, California: Duxbury Press, 1994.
Lua MLA (9ú heag.)Keller, Gerald, agus Brian Warrack. Essentials of Business Statistics. 2nd ed. Duxbury Press, 1994.
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