1. Chow, J. H. and Kokotovic, P. V., A Decomposition of Near Optimum Regulators for Systems with Slow and Fast Modes, I.E.E.E. Trans. on Automatic Control, Vol. 21, no. 5, 1976, pp. 701–705.
2. Grantham, W. J., A Controllability Minimum Principle, Ph.D. dissertation, Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ, 1973.
3. Grantham, W. J., Trajectory Following Optimization by Gradient Transformation Differential Equations, Proc. 42nd I.E.E.E. Conf. on Decision and Control, Maui, HI, December 2003, pp. 5496–5501.
4. O’Malley, R. E., Introduction to Singular Perturbations, Academic Press, New York, 1974.
5. Vincent, T. L. and Grantham, W. J., Nonlinear and Optimal Control Systems, Wiley, New York, 1997.