Freund, J. E., & Williams, F. J. a. (1964). Elementary business statistics: The modern approach. Prentice - hall.
Lua i Stíl Chicago (17ú heag.)Freund, John E., agus Frank J.[et al] Williams. Elementary Business Statistics: The Modern Approach. New Jersey: Prentice - hall, 1964.
Lua MLA (9ú heag.)Freund, John E., agus Frank J.[et al] Williams. Elementary Business Statistics: The Modern Approach. Prentice - hall, 1964.
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