Freud, J. E. (1988). Modern elementary statistics (7th ed.). Prentice-Hall.
Dyfyniad Arddull ChicagoFreud, John E. Modern Elementary Statistics. 7th ed. New Jersey: Prentice-Hall, 1988.
Dyfyniad MLAFreud, John E. Modern Elementary Statistics. 7th ed. Prentice-Hall, 1988.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.