Nesterova N.M. ,     Yakovlev V.I. ,     Kirov I.N. ,     Stamenov J.N. ,     Ushev S.Z. ,     Janminchev V.D. ,     Dubovij A.G. ,     Petrov S.P. ,     Lilkov V.M. Search for shower excess from Gygnus X-3. I-93843 Intern. cosmic ray conf. Aug. 2-15, 1987. Moscow, USSR. Conf.Papers. , Vol.1 , с. P.223-226 , 01.1987