1. Demyanov, V.F., Rubinov, A.M.: Constructive Nonsmooth Analysis. Approximation & Optimization, vol. 7. Peter Lang, Frankfurt am Main (1995)
2. Demyanov, V.F., Stavroulakis, G.E., Polyakova, L.N., Panagiotopoulos, P.D.: Quasidifferentiability and Nonsmooth Modelling in Mechanics, Engineering and Economics Nonconvex Optimization and its Applications, vol. 10. Kluwer Academic Publishers, Dordrecht (1996)
3. Panagiotopoulos, P.D.: Hemivariational Inequalities. Applications in Mechanics and Engineering. Springer, Berlin (1993)
4. Naniewicz, Z., Panagiotopoulos, P.D.: Mathematical Theory of Hemivariational Inequalities and Applications. Marcel Dekker, New York (1995)
5. Panagiotopoulos, P.D.: Inequality Problems in Mechanics and Application. Convex and nonconvex energy functions. Birkhäuser, Basel (1998)