1. A. Saum, J. Polym. Sci.,42, 57 (1960).
2. V. G. Petrosyan, Summary of Thesis [in Russian], Moscow (1973).
3. W. Dannhauser and A. Flueckinger, J. Phys. Chem.,68, 1814 (1964).
4. E. L. Zhukova, Opt. Spektrosk.,4, 75 (1958).
5. A. von A. Kratochwill, J. Weidner, and H. Zimmerman, Ber. Bunsenges. Physik. Chem.,77, 408 (1973).