| [1] | G. Amelino-Camelia, J. Ellis, N. E. Mavromatos et al, Int. J. Mod. Phys. A, 12:607(1997) | 
	
			| [2] | J. Ellis, N. E. Mavromatos, and D. V. Nanopoulos, Phys. Lett. B, 665:412(2008) | 
	
			| [3] | J. Ellis, N. E. Mavromatos, and D. V. Nanopoulos, Int. J. Mod. Phys. A, 26:2243(2011) | 
	
			| [4] | R. Gambini and J. Pullin, Phys. Rev. D, 59:124021(1999) | 
	
			| [5] | J. Alfaro, H. A. Morales-Tcotl, and L. F. Urrutia, Phys. Rev. D, 65:103509(2002) | 
	
			| [6] | J. Ellis, N. Mavromatos, and D. Nanopoulos, Phys. Lett. B, 293:37(1992) | 
	
			| [7] | J. Ellis, N. Mavromatos, and D. Nanopoulos, Chaos, Solitons  Fractals, 10:345(1999) | 
	
			| [8] | G. Amelino-Camelia, Int. J. Mod. Phys. D, 11:35(2002) | 
	
			| [9] | G. Amelino-Camelia, J. Ellis, N. Mavromatos, D. V. Nanopou-los, and S. Sarkar, Nature, 393:763(1998) | 
	
			| [10] | J. Ellis and N. E. Mavromatos, Astropart. Phys., 43:50(2013) | 
	
			| [11] | Z. Chang, Y. Jiang, and H. N. Lin, Astropart. Phys., 36:47(2012) | 
	
			| [12] | L. Shao, Z. Xiao, and B. Q. Ma, Astropart. Phys., 33:312(2010) | 
	
			| [13] | S. Zhang and B. Q. Ma, Astropart. Phys., 61:108(2014) | 
	
			| [14] | V. Vasileiou, A. Jacholkowska, F. Piron et al, Phys. Rev. D, 87:122001(2013) | 
	
			| [15] | A. A. Abdo, M. Ackermann, M. Ajello et al, Nature, 462:331(2009) | 
	
			| [16] | J. Ellis, N. E. Mavromatos, D. V. Nanopoulos et al, Astropart. Phys., 25:402(2006) | 
	
			| [17] | V. Vasileiou, J. Granot, T. Piran et al, Nature Physics, 11:344(2015) | 
	
			| [18] | R. J. Nemiroff, R. Connolly, J. Holmes et al, Phys. Rev. Lett., 108:231103(2012) | 
	
			| [19] | J. Ellis, N. Mavromatos, D. V. Nanopoulos et al, Astron. As-trophys, 402:409(2003) | 
	
			| [20] | S. E. Boggs, C. B. Wunderer, K. Hurley et al, Astrophys. J., 611:L77(2004) | 
	
			| [21] | S. Zhang and B. Q. Ma, Astropart. Phys., 61:108(2015) | 
	
			| [22] | Y. Pan, Y. Gong, S. Cao et al, Astrophys. J., 808:78(2015) | 
	
			| [23] | Z. Xiao and B. Q. Ma, Phys. Rev. D, 80:116005(2009) | 
	
			| [24] | V. A. Kosteleck and M. Mewes, Phys. Rev. Lett., 110:201601(2013) | 
	
			| [25] | T. Kahniashvili, G. Gogoberidze, and B. Ratra, Phys. Lett. B, 643:81(2006) | 
	
			| [26] | S. Coleman and S. L. Glashow, Phys. Rev. D, 59:116008(1999) | 
	
			| [27] | M. Biesiada and A. Pirkowska, Class. Quantum Grav., 26:125007(2009) | 
	
			| [28] | M. Gogberashvili, A. S. Sakharov, and E. K. Sarkisyan, Phys. Lett. B, 644:179(2007) | 
	
			| [29] | B. E. Schaefer, Phys. Rev. Lett., 82:4964(1999) | 
	
			| [30] | P. Kumar and R. B. Duran, Mon. Not. Roy. Astron. Soc., 400:75(2009) | 
	
			| [31] | A. A. Abdo et al, Astrophys. J., 706:L138(2009) | 
	
			| [32] | M. Ackermann et al, Astrophys. J., 716:1178(2010) | 
	
			| [33] | M. Ackermann et al, Astrophys. J., 729:114(2011) | 
	
			| [34] | P. Kumar and B. Zhang, Phys. Rep., 561:1(2015) | 
	
			| [35] | C. Kouveliotou, C. A. Meegan, G. J. Fishman et al, Astrophys. J., 413:L101(1993) | 
	
			| [36] | T. Piran, Phys. Rep., 314:575(1999) | 
	
			| [37] | D. Band, J. Matteson, L. Ford et al, Astrophys. J., 413:281(1993) | 
	
			| [38] | R. D. Preece, G. N. Pendleton, M. S. Briggs et al, Astrophys. J., 496:849(1998) | 
	
			| [39] | N. M. Lloyd and V. Petrosian, Astrophys. J., 543:722(2000) | 
	
			| [40] | G. Amelino-Camelia and L. Smolin, Phys. Rev. D, 80:084017(2009) | 
	
			| [41] | U. Jacob and T. Piran, J. Cosmol. Astropart. Phys., 2008:031(2008) | 
	
			| [42] | J. Ellis, N. E. Mavromatos, D. V. Nanopoulos et al, Astropart. Phys., 29:158(2008) | 
	
			| [43] | P. Ade et al(Planck Collaboration), arXiv:1502.01589 | 
	
			| [44] | G. I. Rubtsov, M. S. Pshirkov, and P. G. Tinyakov, Mon. Not. R. Astron. Soc., 421:L14(2012) |