2Xu R N, Zhai X Y. Extensions of the analytic hierarchy process in fuzzy environment[J]. Fuzzy Sets and Systems, 1992,52:251- 257.
3Saaty T L. The analytical hierarchy process[M]. NowYork:McGraw Hill Inc. , 1986.
4Dyer J,Homsley T,Marshall D,Wise M. Methodoloical analysis for models of the development of energy derived from western coal[R]. EG-625 Group Project Report at the University of Alabama in Huntsville,August, 1974.