1. Agostinelli, S., et al., Nucl. Instrum. Methods Phys. Res. Sect. A, 2003, vol. 502, no. 2, p. 666.
2. Ryazhskaya, O. and Zatsepin, G., Proc. 9th Int. Conf. ICRC, London, 1965, vol. 2, p. 987.
3. Ryazhskaya, O., Phys. Usp., 2013, vol. 56, p. 296.
4. Barashenkov, V.S., Fiz. Elementarn. Chastits Atomn. yadra, 1978, vol. 9, no. 5, p. 871.
5. Bezrukov, L.B., Beresnev, V.I, Niunin, M.I., and Ryazhskaya, O.G., Acta Phys. Hung., 1970, vol. 29, suppl. 4, p. 285.