Wallace, J. P., & Sherret, A. (1973). Estimation of Product Attributes and Thier Importances. Springer-Verlag.
Dyfyniad Arddull ChicagoWallace, J P., and A. Sherret. Estimation of Product Attributes and Thier Importances. Berlin: Springer-Verlag, 1973.
Dyfyniad MLAWallace, J P., and A. Sherret. Estimation of Product Attributes and Thier Importances. Springer-Verlag, 1973.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.