1. Panagiotopoulos, P.O., 1993. Hemivariational Inequalities. Applications in Mechanics and Engineering. Springer-Verlag, Berlin. New York.
2. Panagiotopoulos=, P.O., 1985. Inequality problems in mechanics and applications. Convex and nonconvex energy functions. Birkhäuser Verlag, Boston-Basel-Stuttgart.
3. Panagiotopoulos=, P.O., 1980. Optimal control of unilat eral Structural analysis problems, In: Leipholz, H.H.E, (ed.), Proc. IUTAM Symp. On Structural Control. North-Holland, Amsterdam.
4. Panagiotopoulos=, P.O., 1984. Optimal control of structures with convex and nonconvex energy densities and variational and hemivar iational inequalities, Eng. Struct., 6, 12–18.
5. Nitsiotas, G., 1971. Die Berechnung statisch unbestimmter Tragwerke mit einseitigen Bindungen. Ingenieur-Archiv.
41. 46–60.