Apanasenko A.V. , Baradzei L.T. , Kanevskaya E.A. , Smorodin Y.A. , Rykov V.V. , Solovyev M.V. The spectrum of "gamma" rays in the energy range 10~11 to 10~13 eV at an atmospheric depth of 200 g/cm~2, and pion generation in high-energy nucleon interactions. Can. J. Phys. , Vol.46,N10,pt.3 , с. P.700-705 , 01.1968