[1] L. Collatz and U. Sinogowitz, Spektren endlicher Grafen, Abh. Math. Sem. Univ. Hamburg, 21 (1957) 63–77.
[2] R. Cruz, I. Gutman and J. Rada, Sombor index of chemical graphs, Appl. Math. Comput., 399 (2021) 10 p.
[3] K. C. Das, A.S. Çevik, I. N. Cangul and Y. Shang, On Sombor Index, Symmetry, 13 (2021).
[4] H. Deng, Z. Tang and R. Wu, Molecular trees with extremal values of Sombor indices, Int. J. Quantum Chem., 121
(2021).
[5] B. Furtula and I. Gutman, A forgotten topological index, J. Math. Chem., 53 (2015) 1184–1190.
[6] I. Gutman, The energy of a graph, Ber. Math.-Statist. Sekt. Forschungsz. Graz, 103 (1978) 1–22.
[7] I. Gutman, Topology and stability of conjugated hydrocarbons. The dependence of total π-electron energy on
molecular topology, J. Serb. Chem. Soc., 70 (2005) 441–456.
[8] I. Gutman, Comparative studies of graph energies, Bull. Acad. Serbe Sci. Arts (Cl. Sci. Math. Natur.), 144 (2012)
1–17.
[9] I. Gutman, The energy of a graph: Old and new results, Algebraic Combinatorics and Applications, Springer, Berlin,
(2001) 196–211.
[10] I. Gutman, Geometric approach to degree-based topological indices: Sombor indices, MATCH Commun. Math.
Comput. Chem., 86 (2021) 11–16.
[11] I. Gutman, Some basic properties of Sombor indices, Open J. Discret. Appl. Math., 4 (2021) 1–3.
[12] C. Godsil, Algebraic Combinatorics, Chapman and Hall Mathematics, New York: Chapman and Hall. xv, (1993)
362 p.
[13] I. Gutman and O.E. Polansky, Mathatical Concepts in Organic Chemistry, Springer, Berlin, 1986.
[14] I. Gutman and N. Trinajstić, Graph theory and molecular orbitals. Total π-electron energy of alternant hydrocar-
bons, Chem. Phys. Lett., 17 (1972) 535–538.
[15] W. H. Haemers, Interlacing eigenvalues and graphs, Linear Algebra Appl., 226-228 (1995) 593–616.
[16] Y. Hong, A bound on the spectral radius of graphs, Linear Algebra Appl., 108 (1988) 135–140.
[17] X. Li and Z. Wang, Trees with extremal spectral radius of weighted adjacency matrices among trees weighted by
degree-based indices, Linear Algebra Appl., 620 (2021) 61–75.
[18] V. R. Kulli, Sombor indices of certain graph operators, Int. J. Engin. Sci. Res. Technol., 10 (2021) 127–134.
[19] H. Kober, On the arithmetic and geometric means and on Hölders inequality, Proc. Amer. Math. Soc., 9 (1958)
452–459.
[20] V. R. Kulli and I. Gutman, Computation of Sombor Indices of Certain Networks, Int. J. Appl. Chem., 8 (2021) 1–5.
[21] R. Liu and W. C. Shiu, General Randić matrix and general Randić incidence matrix, Discrete Appl. Math., 186
(2015) 168–175.
[22] X. Li, Y. Shi and I. Gutman, Graph Energy, Springer, New York, 2012.
[23] I. Milovanović, E. Milovanović and M. Matejić, On Some mathematical properties of Sombor indeces, Bull. Int.
Math. Virtual Inst., 11 (2021) 341–353.
[24] V. Nikiforov, Some new results in extremal graph theory, 392, Cambridge Univ. Press, Cambridge, 2011.
[25] I. Redžepović, Chemical applicability of Sombor indices, J. Serb. Chem. Soc., 86 (2021) 445–457.
[26] T. Réti, T. Došlić and A. Ali, On the Sombor index of graphs, Contrib. Math., 3 (2021) 11–18.
[27] D. Stevanović, Spectral Radius of Graphs, Academic Press, Amsterdam, 2015.
[28] M. Taita and J. Tobin, Three conjectures in extremal spectral graph theory, J. Comb. Theory, Ser. B, 126 (2017)
137–161.
[29] D. Vukičević and M. Gašperov, Bond additive modelling 1. Adriatic indices, Croat. Chem. Acta, 83 (2010) 261–273.
[30] Z. Wang, Y. Mao, Y. Li and B. Furtula, On relations between Sombor and other degree-based indices, J. Appl.
Math. Comput., 68 (2022) 1–17.
[31] B. Xu, S. Li, R. Yu and Q. Zhao, On the spectral radius and energy of the weighted adjacency matrix of a graph,
Appl. Math. Comput., 340 (2019) 156–163.
[32] B. Zhou, On the spectral radius of nonnegative matrices, Australas. J. Comb., 22 (2000) 301–306.
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