Volume 36 • Number 2 • 2013   • Extremal Unicyclic and Bicyclic Graphs with Respect to Harary Index Kexiang Xu and Kinkar Ch. Das Abstract. The Harary index is defined as the sum of reciprocals of distances between all pairs of vertices of a connected graph. In this paper, we determined the extremal (maximal and minimal) unicyclic and bicyclic graphs with respect to Harary index. 2010 Mathematics Subject Classification: 05C90 Full text: PDF