| [1] | S. Perlmutter et al (SNCP Collaboration), Astrophys. J, 517: 565 (1999) | 
	
			| [2] | A. G. Riess et al (Supernova Search Team Collaboration), Astron. J, 116: 1009 (1998) | 
	
			| [3] | D. N. Spergel et al (WMAP Collaboration), Astrophys. J. Suppl., 148: 175 (2003); 170: 377 (2007) | 
	
			| [4] | E. Komatsu et al (WMAP Collaboration), Astrophys. J. Suppl., 180: 330 (2009); 192: 18 (2011) | 
	
			| [5] | M. Tegmark et al (SDSS Collaboration), Phys. Rev. D, 69: 103501 (2004) | 
	
			| [6] | U. Seljak et al (SDSS Collaboration), Phys. Rev. D, 71: 103515 (2005) | 
	
			| [7] | D. J. Eisenstein et al (SDSS Collaboration), Astrophys. J, 633: 560 (2005) | 
	
			| [8] | B. Jain and A. Taylor, Phys. Rev. Lett., 91: 141302 (2003) | 
	
			| [9] | P. Ade et al (Planck Collaboration), Astron. Astrophys., 571: A16 (2014); 571: A22 (2014) | 
	
			| [10] | P. Ade et al (BICEP2 Collaboration), Phys. Rev. Lett., 112: 241101 (2014) | 
	
			| [11] | R. R. Caldwell and M. Kamionkowski, Ann. Rev. Nucl. Part. Sci., 59: 397 (2009) | 
	
			| [12] | L. Amendola and S. Tsujikawa, Dark Energy (Cambridge University press, 2010) | 
	
			| [13] | M. Li, X. D. Li, S. Wang, and Y. Wang, Commun. Theor. Phys., 56: 525 (2011) | 
	
			| [14] | M. Kunz, Comptes Rendus Physique, 13: 539 (2012) | 
	
			| [15] | T. Chiba, N. Sugiyama, and T. Nakamura, Mon. Not. Roy. Astron. Soc., 289: L5 (1997) | 
	
			| [16] | R. R. Caldwell, R. Dave, and P. J. Steinhardt, Phys. Rev. Lett., 80: 1582 (1998) | 
	
			| [17] | Y. Fujii, Phys. Rev. D, 26: 2580 (1982) | 
	
			| [18] | R. R. Caldwell, Phys. Lett. B, 545: 23 (2002) | 
	
			| [19] | T. Padmanabhan, Phys. Rev. D, 66: 021301 (2002) | 
	
			| [20] | A. Y. Kamenshchik, U. Moschella, and V. Pasquier, Phys. Lett. B, 511: 265 (2001) | 
	
			| [21] | M. C. Bento, O. Bertolami, and A. A. Sen, Phys. Rev. D, 66: 043507 (2002) | 
	
			| [22] | N. Bilic, G. B. Tupper, and R. D. Viollier, Phys. Lett. B, 535: 17 (2002); Phys. Rev. D, 80: 023515 (2009) | 
	
			| [23] | M. Li, Phys. Lett. B, 603: 1 (2004) | 
	
			| [24] | E. Elizalde, S. Nojiri, S. D. Odintsov, and P. Wang, Phys. Rev. D, 71: 103504 (2005) | 
	
			| [25] | S. Nojiri and S. D. Odintsov, Gen. Rel. Grav., 38: 1285 (2006) | 
	
			| [26] | M. Vasilic, Class. Quant. Grav., 15: 29 (1998) | 
	
			| [27] | B. Guberina, R. Horvat and H. Stefancic, JCAP, 05: 001 (2005) | 
	
			| [28] | H. Kim, H. W. Lee and Y. S. Myung, Phys. Lett. B, 628: 11 (2005) | 
	
			| [29] | X. Zhang, Phys. Rev. D, 74: 103505 (2006); Phys. Lett. B, 648: 1 (2007) | 
	
			| [30] | M. R. Setare, Phys. Lett. B, 648: 329 (2007); 653: 116 (2007); Eur. Phys. J. C, 50: 991 (2007) | 
	
			| [31] | J. Zhang, X. Zhang and H. Liu, Phys. Lett. B, 651: 84 (2007) | 
	
			| [32] | W. Zhao, Phys. Lett. B, 655: 97 (2007) | 
	
			| [33] | M. R. Setare and E. N. Saridakis, Phys. Lett. B, 671: 331 (2009) | 
	
			| [34] | N. Cruz, P. F. Gonzalez-Diaz, A. Rozas-Fernandez and G. Sanchez, Phys. Lett. B, 679: 293 (2009) | 
	
			| [35] | K. Karami and J. Fehri, Phys. Lett. B, 684: 61 (2010) | 
	
			| [36] | A. Rozas-Fernandez, Eur. Phys. J. C, 71: 1536 (2011) | 
	
			| [37] | M. Blagojevic, Gravitation and Gauge Symmetries (Institute of Physics Publishing, Bristol, 2002) | 
	
			| [38] | L. F. Abbott and S. Deser, Nucl. Phys. B, 195: 76 (1982) |