1. T. Timusk and D. B. Tanner,Infrared properties of high-temperature superconductors, in: Physical properties of high temperature superconductors. Editor: D. M. Ginsberg, World Scientific, Singapore, New Jersey, London, Hong Kong, 1989.
2. K. F. Renk,Far-infrared spectroscopy of high-temperature super-conductors, in: Studies of High Temperature Superconductors. Editor: A. V. Narlikar, Nova Science Publishers, New York, Vol. 10, 1992.
3. R. E. Glover, and M. Tinkham, Phys. Rev.104, 844 (1956).
4. D. M. Ginsberg and M. Tinkham, Phys. Rev.118, 990 (1960).
5. A. T. Grigoriev, B. S. Danilin, V. I. Makhov, and A. V. Tyablikov, Sov. Electronnaya Tekhnika,6, 14 (1982).