1. Karl Johan Åström and K. Furuta. Swinging up a pendulum by energy control. In IFAC'96, Preprints 13th World Congress of IFAC, volume E, pages 37–42, San Francisco, California, July 1996.
2. A. F. Filippov. Differential Equations with Discontinuous Righthand Sides. Kluwer Academic Publishers, 1988.
3. Jörgen Malmborg, Bo Bernhardsson, and Karl Johan Åström. A stabilizing switching scheme for multi controller systems. In IFAC'96, Preprints 13th World Congress of IFAC, pages 229–234, San Francisco, California, July 1996.
4. Jerrold E Marsden. Lectures on Mechanics. Cambridge University Press, 1992, Cambridge, U.K., 1992.
5. Marc H. Raibert. Legged Robots that balance. MIT Press, Cambridge, MA, 1986.