1. S.A. Balbus, in: A. Ferrara, C.F. McKee, C. Heiles, P.R. Shapiro (Eds.), Astronomical Society of the Pacific, San Francisco, ASP Conference Series, Vol. 80, p. 328.
2. A. Kudrolli, J.P. Gollub, Powders & Grains 97, Balkema, Rotterdam, 1997, p. 535.
3. J.S. Olafsen, J.S. Urbach, Phys. Rev. Lett. 81 (1998) 4369, cond-mat/9807148.
4. J.S. Olafsen, J.S. Urbach, cond-mat/9905173, unpublished.
5. W. Losert, D.G.W. Cooper, J.P. Gollub, Phys. Rev. E 59 (1999) 5855, cond-mat 9901203.