1. V. A. Smith A. V. Semenovskii, P. F. Vlad, and V. F. Kucherov, Izv. AN SSSR. Otd, khim. n. 1962, 312.
2. P. Bächli and H. Schinz, Helv. chim. acta34, 1160 (1951).
3. B. A. Rudenko, V. F. Kucherov, V.A.Srnith and A. V. Semenovskii, Izv. AN SSSR. Otd. khim. n. 1962, 236.
4. L. Purlee and R. Taft, J. Amer. Chem. Soc.78, 5807 (1956).
5. F. Tiernann, Ber.33, 3719 (1900).