1. Adams, R.A.: Sobolev Spaces. Academic Press, New York (1975)
2. Aliabadi, M.H., Brebbia, C.A.: Advanced Formulations in Boundary Element Methods. Southampton Computational Mechanics Publications (1993)
3. ANSYS version 5.5, User’s Manual. Ansys Engineering Systems, Houston (1999)
4. Balinski, M.L., Wolfe, P.: Mathematical Programming Study 3: Nondifferentiable Optimization. North-Holland Publishing Company, Amsterdam (1975)
5. Bathe, K.J.: Finite Element Procedures. Prentice-Hall, New Jersey (1996)