Freund, J. E. (1973). Modern elementary statistics (4th ed.). Prentice-Hall.
Dyfyniad Arddull ChicagoFreund, John E. Modern Elementary Statistics. 4th ed. Englewood Cliffs, N.J: Prentice-Hall, 1973.
Dyfyniad MLAFreund, John E. Modern Elementary Statistics. 4th ed. Prentice-Hall, 1973.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.