[2] Cvetkovic, D., Rowlinson, P., & Simic, S. (2010). An Introduction to the Theory of Graph Spectra, Cambridge University Press, Cambridge.
[4] Suil, O., Yongtang S., & Zheny T (2021). Sharp upper bounds on the k-independence number in graphs with given minimum and maximum degree, Graphs Combin. 37, 393{408.
https://doi.org/10.1007/s00373-020-02244-y
[5] Li, X., Shi, Y., & Gutman, I. (2012), Graph Energy, Springer-Verlag, New York.
[7] West, D. B. (2001) Introduction to Graph Theory, 2nd ed., Prentice Hall, Upper Saddle River.