1. Szefer's theory is exhaustively developed inG. Szefer:Symposium Franco-Polonais, Problèmes non linéaires de mécanique (Cracovie, 1977), p. 585.
2. M. A. Biot:J. Appl. Phys.,33, 1482 (1962);J. Acoust. Soc. Am.,34, 1254 (1962).
3. For a complete review of the theory of mixtures and its applications seeR. J. Atkin andR. E. Craine:Q. J. Mech. Appl. Math.,29, 209 (1976);J. Inst. Math. Its Appl.,7, 153 (1976).
4. G. Szefer andG. Pallotti:Biomechanics (in press).
5. The summation convention is understood to apply to repeated, indices. Small Roman indices take the values 1, 2, 3, capital Roman indices take the values 1, 2, …, 13. Small Greek indices take the values 1, 2. The components of $$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\thicksim}$}}{t} $$ in (2) are given by $$l_{ij} (x,t) = \int\limits_0^t {C_{ijkl} } (t - \tau )\dot e_{kl} (x,\tau )d\tau + \int\limits_0^t {\frac{{A(t - \tau )}}{R}} \dot p(x,\tau )d\tau \delta _{ij} $$ .