Witte, R. S. (1993). Student workbook to accompany statistics (4th.ed.). HBJ.
Lua i Stíl Chicago (17ú heag.)Witte, Robert S. Student Workbook to Accompany Statistics. 4th.ed. Orlando: HBJ, 1993.
Lua MLA (9ú heag.)Witte, Robert S. Student Workbook to Accompany Statistics. 4th.ed. HBJ, 1993.
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