1. Berichte,17, 2816 (1884).
2. US Pat. 3,006,977 (1961).
3. G. L. Natanson and M. Ya. Kogan, Zh. Fiz. Khim.,17, Nos. 5?6, 381 (1943).
4. Yu. G. Mamedaliev and G. M. Mamedaliev, Izv. Akad. Nauk SSSR, Otd. Khim. Nauk, No. 8, 986 (1956).
5. Ya. I. Isakov and Kh. M. Minachev, Neftekhimiya,10, No. 6, 805 (1970).