Nesterova N.M. ,     Romakhin V.A. ,     Kirov I.N. ,     Stamenov J.N. ,     Ushev S.Z. ,     Kabanova N.V. ,     Yanminchev V.D. ,     Stanev T.S. ,     Betev B.. ,     Markovsky B.. ,     Vankov H.. Investigation of EAS fluctuations of the muon component of extensive air showers at mountain altitudes. 14-th Intern. Cosmic Ray Conf. Proc. Munich 1975 , Vol.8 , с. (3 печ. л.) , 01.1975