1. Ya.T.Éidus and K.V.Puzitskii, Usp.Khim.,33, 91 (1964); K.V.Berd, ibid.,33, 1304 (1964).
2. G.A.Elliot and S.A.Furbush, US Patent No. 3002016 (1961);
3. Ref.Zh.Khim., 3H59 (1963);
4. R.Stadler and H.Lautenschlager, German Patent Nos. 1060382 and 1064503 (1960);
5. Ref.Zh.Khim., 12A55, 18A63 (1961).