1. Nonlinear Structures in Physical Systems: Pattern Formation, Chaos and Waves, edited by L. Lam and H.C. Morris (Springer, New York, 1990).
2. Random Fluctuations and Pattern Growth: Experiments and Models, edited by H.E. Stanley and N. Ostrowsky (Kluwer, Boston, 1988).
3. P.G. Saffman, in Ref. [1].
4. L. Lam, in Wave Phenomena, edited by L. Lam and H.C. Morris (Springer, New York, 1989 ).
5. L. Lam et al, Liq. Cryst. 5, 1813 (1989).