1. Stochastic theory of minimal realization
2. BILLINGS , S. A. , and LEONTARITIS , I. J. , 1981 ,Proc. I.E.E. Conf. on Control and Its Applications,Warwick, p. 183 ; 1982 ,6th I.F.A.C. Symp. on Identification and System Parameter Estimation,Washington , D.C., p. 427 .