Freund, J. E., Williams, F. J., Perles, B. M., & Sullivan, C. (1969). Modern business statistics (10th ed.). Prentice Hall.
Cita Chicago (17th ed.)Freund, John E., Frank Jefferson Williams, Benjamin M. Perles, i Charles Sullivan. Modern Business Statistics. 10th ed. Englewood Cliffs, N.J: Prentice Hall, 1969.
Cita MLA (9th ed.)Freund, John E., et al. Modern Business Statistics. 10th ed. Prentice Hall, 1969.
Atenció: Aquestes cites poden no estar 100% correctes.