“…For some years different experimental observations have claimed the possibility of selecting, among showers initiated by the different primary nuclei, those induced by primary y-quanta (Samorski and Stamm 1983a, Lloyds-Evans et a1 1983, Dzikowski et a1 1983, Stamenov et a1 1983, Nikolsky et a1 1984, Protheroe et a1 1984, Boone et a1 1984. Excepting the Tien Shan observations, all these experimental analyses are based on the excess of showers from the direction of local point sources.…”