Freund, J. E., & Williams, F. J. (1982). Elementary business statistics: The modern approach (4th ed.). Prentice-Hall International.
Cita Chicago (17th ed.)Freund, John E., i Frank Jefferson Williams. Elementary Business Statistics: The Modern Approach. 4th ed. London: Prentice-Hall International, 1982.
Cita MLA (9th ed.)Freund, John E., i Frank Jefferson Williams. Elementary Business Statistics: The Modern Approach. 4th ed. Prentice-Hall International, 1982.
Atenció: Aquestes cites poden no estar 100% correctes.