1. M. Abramowitz and I. Stegun. Handbook of Mathematical Functions. Dover, 1964.
2. M. A. Aizerman and F. R. Gantmakher. On the stability of equilibrium positions in discontinuous systems. Prikl. Mat. i Mekh., 24:283–93, 1960.
3. M. A. Aizerman and E. S. Pyatnitskii. Fundamentals of the theory of discontinuous systems I,II. Automation and Remote Control, 35:1066–79, 1242–92, 1974.
4. J. C. Alexander and T. I. Seidman. Sliding modes in intersecting switching surfaces, i: Blending. Houston J. Math, 24(3):545–569, 1998.
5. J. C. Alexander and T. I. Seidman. Sliding modes in intersecting switching surfaces, ii: Hysteresis. Houston J. Math, 25(1):185–211, 1999.