4Michael W Bbbcock, Xiaohua Lu, Jerry Norton. Time Series Forecasting of Quarterly Railroad Grain Carloadings [J]. Transportation Research, 1999, Part E(35) :43 - 57.
5Bates J M, Granger C W J. The Combination of Forecasts [ J ]. Operational Research Quarterly, 1969, 20 (4) : 451 - 468.
6Holden K, Peel D A. Unbiasedness, Efficiency and the Combination of Economic forecasts [ J ]. Journal of Forecasting, 1989, 8(3) :175 - 188.