1. Acerbi, E. and Fusco, N.: Semicontinuity problems in the calculus of Variations, to appear in Arch. Rat. Mech. Anal.
2. Adams, R.A.: 1975, Sobolev Spaces, Academic Press, New York.
3. Ball, J.M.: 1977, Convexity conditions and existence theorems in nonlinear elasticity, Arch. Rat. Mech. Anal. 63, pp. 337 – 403.
4. Berliocchi, H. and Lasry, J.M.: 1973, Intégrandes normales et mesures paramétrees en calcul des variations, Bull. SMF 101, pp. 129 – 184.
5. Callen, H.B.: 1968, Thermodynamics, Wiley, New York and London.