1. Zubov, L. M.: The stationary principle of complementary work in nonlinear theory of elasticity. PMM 34 (1970) 228?232
2. Koiter, W. T.: On the principle of stationary complementary energy in the non-linear theory of elasticity. SIAM J. Appl. Math. 25 (1973) 424?434
3. Koiter, W. T.: On the complementary energy theorem in nonlinear elasticity theory. In: Fichera, G. (Ed.): Trends in Applications of Pure Mathematics to Mechanics, 207?232. London 1976
4. Stumpf, H.: Dual extremum principles and error bounds in non-linear elasticity theory. 14-th Int. Congr. Appl. Mech. (IUTAM), Delft 1976, J. Elasticity 8/4 (1978) 425?438
5. Stumpf, H.: Stationarit�ts- und Extremalprinzipe der geometrisch-nichtlinearen Plattentheorie. Wiss. Z. Hochs. Bauwes. Weimar 22/2 (1975) 236?239