1. The energy of a graph;Gutman;Ber. Math. Stat. Sekt. Forschungszent. Graz,1978
2. The Energy of a Graph: Old and New Results;Gutman,2001
3. R.A. Brualdi, Energy of a Graph. .
4. Hyperenergetic molecular graphs;Gutman;J. Serb. Chem. Soc.,1999
5. The energy of some graphs with large number of edges;Gutman;Bull. Acad. Serbe Sci. Arts,1999