1] J. A. Bondy and U. S. R. Murty, Graph Theory, 244, Springer, New York, 2008.
[2] S . B. Bozkurt and I. Gutman, Estimating the incidence energy, MATCH Commun. Math. Comput. Chem., 70 (2013) 143–156.
[3] G. Caporossi, I. Gutman, P. Hansen and L. Pavlovic, Graphs with maximum connectivity index, Comput. Biol. Chem., 27 (2003) 85–90.
[4] F. R. K. Chung, Spectral Graph Theory, Amer. Math. Soc., Providence, 1997.
[5] D. Cvetkovic, M. Doob and H. Sachs, Spectra of Graphs-Theory and Application, Third ed., Johann Ambrosius Barth. Heidelberg, 1995.
[6] D. Cvetkovic, P. Rowlinson and S. Simic, Signless Laplacians of finite graphs, Linear Algebra Appl., 423 (2007) 155–171.
[7] K. C. Das and I. Gutman, On incidence energy of graphs, Linear Algebra Appl., 446 (2014) 329–344.
[8] R. Gu, F. Huang and X. Li, General Randi´ c matrix and general Randic energy, Trans. Comb., 3 no. 3 (2014) 21-33.
[9] I. Gutman, The energy of a graph, Ber. Math.-Statist. Sekt. Forsch. Graz, 103 (1978) 1–22.
[10] I. Gutman, B. Furtula and S . B. Bozkurt, On Randic energy, Linear Algebra Appl., 442 (2014) 50–57.
[11] I. Gutman, D. Kiani and M. Mirzakhah, On incidence energy of graphs, MATCH Commun. Math. Comput. Chem., 62 (2009) 573–580.
[12] I. Gutman, D. Kiani, M. Mirzakhah and B. Zhou, On incidence energy of a graph, Linear Algebra Appl., 431 (2009) 1223–1233.
[13] I. Gutman and O. E. Polansky, Mathematical Concepts in Organic Chemistry, Springer, Berlin, 1986.
[14] M. Jooyandeh, D. Kiani and M. Mirzakhah, Incidence energy of a graph, MATCH Commun. Math. Comput. Chem., 62 (2009) 561–572.
[15] X. Li, Y. Shi and I. Gutman, Graph Energy, Springer, New York, 2012.
[16] V. Nikiforov, The energy of graphs and matrices, J. Math. Anal. Appl., 326 (2007) 1472–1475.
[17] M. Randic, On characterization of molecular branching, J. Amer. Chem. Soc., 97 (1975) 6609–6615.
[18] P. Yu, An upper bound on the Randi´ c index of trees, (Chinese), J. Math. Study, 31 (1998) 225–230.