1. Zel’dovich International Center for Astrophysics, M. Akmullah Bashkir State Pedagogical University, 3A, October Revolution Street, Ufa 450008, RB, Russia
2. Institute of Molecule and Crystal Physics, Ufa Federal Research Centre, Russian Academy of Sciences, Prospekt Oktyabrya 151, Ufa 450075, Russia
3. High Energy Cosmic Ray Research Center, University of North Bengal, Darjeeling 734 013, WB, India