Lewis,John Parry, & Traill,Alasdair. (1999). Statistics explained. Addison-Wesley.
Dyfyniad Arddull ChicagoLewis,John Parry, and Traill,Alasdair. Statistics Explained. England: Addison-Wesley, 1999.
Dyfyniad MLALewis,John Parry, and Traill,Alasdair. Statistics Explained. Addison-Wesley, 1999.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.