1. Analyse convexe et problèmes variationnels;Ekeland,1974
2. Determination of fracture zone properties in mixed mode;Hassanzadeh;Eng. Fract. Mech.,1990
3. Printsip predelnoi naprezennosti;Feinberg;Prikl. Matem. Mehanika,1948
4. Heinisuo, M., 1983. Kosketusprobleeman analyyttinen ratkaiseminen (in Finnish). Licentiate thesis, Tampere University of Technology
5. The Mathematical Theory of Plasticity;Hill,1950