1. D. Bonchev and D. H Rouvray, Chemical topology: Introduction and fundamentals, CRC Press (1999).
2. A. T. Balaban, J. Chem. Inf. Comput. Sci., 25, 334 (1985).
3. R. B. King, D. H. Rouvray, Graph theory and topology in chemistry, Elsevier, Amsterdam (1987).
4. R. Todeschini and V. Consonni, The handbook of molecular descriptors, Wiley-VCH, Weinhei (2000).
5. R. B. King and R. Bruce King, Chemical applications of topology and graph theory, Elsevier, Amsterdam (1983).