Gilles Klopman Chandan Raychaudhury Vertex indexes of molecular graphs in structure-activity relationships: a study of the convulsant-anticonvulsant activity of barbiturates and the carcinogenicity of unsubstituted polycyclic aromatic hydrocarbons. 12-19 1990 30 Journal of Chemical Information and Computer Sciences 1 http://pubs.acs.org/cgi-bin/archive.cgi/jcisd8/1990/30/i01/f-pdf/f_ci00065a004.pdf db/journals/jcisd/jcisd30.html#KlopmanR90