1. Hill, R.: The Mathematical Theory of Plasticity. Oxford University Press, London (1978).
2. Hill, R.: private communication (1976).
3. Bassani, J.L.: Yield characterization of metals with transver-sely isotropic plastic properties. Int. J. Mech. Sci. 19 (1977) 651–660.
4. Hutchinson, J.W.; Neale, K.W.: Sheet necking - II Time-inde-pendent behaviour. Proc. GM Symp. on Mechanics of Sheet Metal Forming. Plenum Press, New York (1978).
5. Hutchinson, J.W.; Neale, K.W.: Sheet necking - III Strain-rate effects. ibid.