1. Midwinter, J. E., Nature, 261, 371–376 (1976).
2. Tamir, T. (ed.), Integrated Optics, Topics in Applied Physics (Springer-Verlag, 1975).
3. Pitt, C. W., Gfeller, F., and Stevens, R., Thin Solid Films, 26, 25–51 (1975).
4. Schmidt, R. V., and Kaminow, I. P., Appl. phys. Lett., 25, 458–460 (1974).
5. Sopori, B. L., and Chang, W. S. C., Topical Meeting on Integrated Optics, 1976 (Optical Society of America, Washington, DC).