1. Network Analysis and Synthesis: A Modern Systems Theory Approach;Anderson,1973
2. W.S. Gray, J. Mesko, Controllability and observability functions for model reduction of nonlinear systems, Proc. 1996 Conf. on Information Sciences and Systems, Princeton, NJ, 1996, pp. 1244–1249.
3. W.S. Gray, J. Mesko, General input balancing transformations for nonlinear systems, Proc. 1997 Conf. on Information Sciences and Systems, Baltimore, MD, 1997, pp. 264–269.
4. W.S. Gray, J. Mesko, General input balancing and model reduction for linear and nonlinear systems, Proc. 1997 European Control Conf., Brussels, Belgium, 1997.
5. A. Isidori, A. Ruberti, Realization theory of bilinear systems, in: D.Q. Mayne, R.W. Brockett (Eds.), Geometric Methods in System Theory, Reidel, Dordrecht, 1973, pp. 83–130.