7Rodger E.Ziemer,William H.Tranter,D.Ronald Fannin.Signals and Systems_Continuous and Discrete(Fourth Edition)[M].Publishing House of Electronics Industry,2005
9Mike Foley, Anjan Bose. An Object Based Graphical Us- er Interface for Power Systems[J]. IEEE Transactions on Power Systems, 1993,8 ( 1 ) : 97 -- 104.