1. Optimal control via mathematical programming
2. Sage, A.P., Optimum Systems Control, Prentice-Hall, Englewood Cliffs, N.J., 1968, pp.367-372.
3. 3Gelfand, I.M. and Fomin, S.V., Calculus of Variations, Prentice-Hall, Englewood Cliffs, N.J., 1963, pp.193-199.
4. Method of Gradients