1. P. A. Semenov and Ya. V. Shvartsshtein, Khim. Prom., No. 9 (1952).
2. P. A. Semenov and Ya. V. Shvartsshtein, Khim. Prom., No. 7 (1953).
3. Ya. V. Shvartsshtein, Khim. Prom., No. 5 (1957).
4. G. Adolphi and G. Fleisher, R. Chem. Tech., No. 11, 638 (1955).
5. V. V. Kafarov, Khimicheskaya Nauka i Promyshlennosti,2, 81 (1967).