Danilova T.V. , Tukish E.I. , Erlykin A.D. , Mironov A.V. Nuclear cascades in electromagnetic showers produced by primary gamma-quanta in the atmosphere. II-19331 19th Intern.cosmic ray conf. La Jolla, USA, Aug.11-23, 1985.Conf.papers , Vol.7 , с. P.260-263 , 01.1985