1. Topological indices and real number vertex invariants based on graph eigenvalues or eigenvectors;Balaban;J. Chem. Inf. Comput. Sci.,1991
2. Digraphs Theory, Algorithms and Applications;Bang-Jensen,2001
3. The circular chromatic number of a digraph;Bokal;J. Graph Theory,2004
4. Graph Theory With Applications;Bondy,1976
5. On the structure-dependence of the largest eigenvalue of distance matrix of an alkane;Gutman;Indian J. Chem. A,1998