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2. J. S. Bakos, I. B. Földes and Zsuzsa Sörlei, Phys. Lett.,75A, 208, 1980.
3. J. S. Bakos, I. B. Földes and Zsuzsa Sörlei, J. Appl. Phys.,52, 627, 1981.
4. The term “self-focusing” is used here in the sense that the induced change in the refraction index causes the observed effect although the focusing itself probably does not really take place to full extent.
5. L. C. Johnson and T. K. Chu, Phys. Rev. Lett.,32, 517, 1974.