1. Coy, R.N., England, C.D., Pearce, D., Reid, R.J.O., and Watson, A.A.: 1981, P 17th ICCR, Paris, 6, pp. 43–6.
2. Chantler, M.P., Craig, M.A.B., McComb, T.J.L., Orford, K.J., Turver, K.E. and Walley, G.M.: 1982, J. Phys. Gf 8, L51–5.
3. Grigorov, N.L., Gubin, Yu.V., Rapoport, I.D., Savenko, I.A., Yakovlev, B.N., Akimov, V.V. and Nesterov, V.E.: 1971, P 12th ICCR, Hobart, 5, pp. 1746–59.
4. Danilova, T.V., Kabanova, N.V., Nesterova, N.M., Nikolskaya, N.M., Nikolsky, S.I., Katsarky, L.M., Kirov, I.N., Stamenov, J.N. and Janminchev, V.D.: 1977, P 15th ICCR, Plovdiv, 8, pp. 129–32.
5. Efimov, N.N.: 1981, private communication, and Bulleten1 NTI Yakutskogo Filiala SO AN SSSR, Aug. 1981.