1. S.P. Bhat and D.S. Berstein, Lyapunov analysis of finite-time differential equations, Proc. Am. Control. Conf. 3 (1995), 1831--1832.
2. R.E. Bellman, Dynamic Programming, Princeton University Press, Princeton, 1957.
3. V.G. Boltyanskii, Mathematical Methods of Optimal Control, (Russian), Nauka, Moscow, 1969.
4. M.D. Choi, Tricks and treats with the Hilbert matrix, Am. Math. Mon. 90 (1983), 301--312.
5. A.E. Choque-Rivero, The controllability function method for the synthesis problem of a nonlinear control system, Int. Rev. Autom. Control 1 (2008), 441--445.