Natkamol Chintakowit และ Parames Chutima. (2007) Improvement of demand forecasting system : cale study in PVC leather and plastic company. Chulalongkorn University:ม.ป.ท.Natkamol Chintakowit และ Parames Chutima. 2007. Improvement of demand forecasting system : cale study in PVC leather and plastic company. ม.ป.ท.:Chulalongkorn University;Natkamol Chintakowit และ Parames Chutima. Improvement of demand forecasting system : cale study in PVC leather and plastic company. ม.ป.ท.:Chulalongkorn University, 2007. Print.