P. Billingsley, Probability and Measure, John Wiley & Sons, New York, 1885.
 Z. Che and Z. Chen, Lower and upper bounds of the forgotten topological
index, MATCH Commun. Math. Comput. Chem. 76 (2016) 635–648.
 T. Doslic, T. Réti and D. Vukicevic, On the vertex degree indices of connected
graphs, Chem. Phys. Lett. 512 (2011) 283–286.
 B. Furtula and I. Gutman, A forgotten topological index, J. Math. Chem. 53
 W. Gao, M. R. Farahani and L. Shi, Forgotten topological index of some drug
structures, Acta Med. Medit. 32 (2016) 579–585.
 I. Gutman and N. Trinajstic, Graph theory and molecular orbitals. Total
-electron energy of alternant hydrocarbons, Chem. Phys. Lett. 17 (1972)
 R. Kazemi, The eccentric connectivity index of bucket recursive trees, Iranian
J. Math. Chem. 5 (2014) 77–83.
 Y. C. Sun, Z. Lin, W. X. Peng, T. Q. Yuan, F. Xu, Y. Q. Wu, J. Yang, Y. S.
Wang and R. C. Sun, Chemical changes of raw materials and manufactured
binderless boards during hot pressing: lignin isolation and characterization,
BioResources 9 (2014) 1055–1071.