1. A. A. Akhrem, I. V. Vesela, and A. V. Kamernitskii, Izv. Akad. Nauk SSSR, Ser. Khim., 416 (1974).
2. J. Fried, US Patent 3049540 (1962);
3. Chem. Abstr., 5763 (1963).
4. V. Petrow, Chem. Rev.,70, 713 (1970).
5. V. Petrow and G. O. Weston, US Patent 3040035 (1962); Chem. Abstr.,57, 15195 (1962).