[1] Hillas A., 1996, Space Science Review, 75, 17
[2] Heck D. et al., 1998, FZKA report 6019
[3] Kalmykov N. N. et al., 1997, Nucl. Phys. B (Proc. Suppl.), 52B, 17
[4] Heck D. and Engel R., 2003, Proc. 28th ICRC, 7, 279
[5] Nelson W.R., Hirayama H. and Rogers D.W.O., 1985, Stanford Linear Accelerator Center Report SLAC-265
[6] Pezeshkian Y., 2011, Proc. 32nd ICRC, 3, 40
[7] Rastegarzadeh G. and Najmi M., 2010, Iranian J. Phys. Res., 10, 169
[8] Arqueros F. et al., 1996, Astropart. Phys., 4, 309
[9] Portocarrero C. E. and Arqueros F., 1998, J. Phy. G: Nuc. Part. Phys., 24, 235
[10] Sobczynska D., 2009, Proc. 31st ICRC, 1, 116
[11] Korosteleva E. et al., 2003, Proc. 28th ICRC, 1, 89
[12] Cortina J. et al., 1997, J. Phys. G: Nuc. Part. Phys., 23, 1733
[13] Lindner A., 1998, Astropart. Phys., 8, 235
[14] Mavrodiev S. C. et al., 2004, NIMA, 530, 359
[15] Mishev A. et al., 2007, Frontiers in Cosmic Ray Research, Nova Science
[16] Hedayati Kh. H. et al., 2011, APJ, 727, 66
[17] Mortazavi Moghaddam S. et al., 2012, Astropart. Ph., 35, 792
[18] Abdollahi S. et al., 2013, J. Phys. G.: Nuc. Part. Phys., 40, 025202
[19] Kalmykov N. N. et al., 1983, Proc. 18th ICRC, 11, 383
[20] Bertaina M. et al., 2001, Proc. 27th ICRC, 1, 14
[21] Al-Rubaiee A.A. et al., 2012, Journal of College of Basic Education, 74, 1
[22] Kuhlmann J. D. et al., 1981, J. Phys. G: Nuc. Part. Phys., 7, 183
[23] Efimov N. N. et al., 1989, Proc. Sov. CRC Alma-Ata, 1, 17
[24] Aliev N. et al., 1985, Proc. 19th ICRC, 7, 107
[25] Alexandrov L., Mavrodiev S.Cht. and Mishev A., 2001, Proc. 27 ICRC, 257
[26] Mavrodiev S., Mishev A. and Stamenov J., 2003, Proc. 28th ICRC, 163
[27] Al-Rubaiee A.A. et al., 2005, Proc. 29th ICRC, 6, 249
[28] Anokhina A. M. et al. 1993, Astrophysics and Space Science, 209, 19
[29] Mishev A. et al., 2005, Int. J. Mod. Phys. A, 20, 7016
[30] Prosin V. V. et al., 2009, Nuc. Phys. B, 190, 247
[31] Grupen C., 2005, Astroparticle Physics, Springer, Berlin
[32] Pezeshkian Y. et al., 2013, Proc. 17th Meeting on Research in Astronomy of Iran, 71
[33] Weekes T. C., 1996, Space Science Reviews, 75, 1
[34] Hillas A. M., 2013, Astropart. Phys., 43, 19