1. Yu. P. Zaitsev, V. A. Zazhigalov, H. Wolf, N. Vyustnek: Proc. 3d Soviet Symposium on Heterogeneous Catalysis in the Chemistry of Heterocyclic Compounds, p. 42, Zinatne, Riga 1981.
2. E. Bordes, P. Courtine: J. Catal.,57, 236 (1979).
3. R. A. Skolmeistere, O. V. Orbidane, L. Ya. Leitis, M. V. Shimanskaya: React. Kinet. Catal. Lett.,15, 251 (1980).
4. Z. I. Yezhkova, I. I. Ioffe, V. B. Kazanskii, A. V. Krylova, A. G. Lyubarskii, L. Ya. Morgolis: Kinet. Katal.,5, 861 (1964).
5. V. V. Krasnikov, Z. A. Konstant: Izv. Akad. Nauk USSR, Inorganic Substances,15, 2164 (1979).