Bondy J A,Mutry.Graph Theory with Application[M].New York:Macmillan,1976.

Hosoya H.Topological index.A newly proposed quantity characterizing the topological nature of struetural isomers of saturatal hydrolarbons[J].Bull Chem Soc Jpn,1971,44:2332-2339.

Gutman I.Extremal hexagonal chains[J].J Math Chem,1993,12:197-210.

Zhang L Z.The Z-transformation graph of perfect matchings of a catacondensed hexagonal system[J].J Math Study,1998,31:437-441.

Zhang L Z,Tian F.Extremal hexagonal chains concerning largest eigenvalue[J].Sci China Ser A,2001,44:1089-1097.

Zhang L Z,Tian F.Extremal catacondensed benzenoids[J].J Math Chem,2003,34:111-122.

Gutman I,Polansky O E.Mathematical Concepts in Organic Chemistry[M].Berlin:Springer-verlag,1986.

Hou Y.On acyclic systems with minimal Hosoya index[J].Discrete Appl Math,2002,119:251-257.

Yu A,Tian F.A kind of graphs with minimal Hosoya indices and maximal Merrifield-Simmons indices[J].MATCH Commun Math Comput Chem,2006,55(1):103-118.

Yu A,Lv X.The Merrifield-Simmons indices and Hosoya indices of trees with k pendent vertices[J].J Math Chem,2007,41(1):33-43.

Ou J.On extremal unicyclic molecular graphs with maximal Hosoya index[J].Discrere Appl Math,2009,157:391-397.

Ou J.On extremal unicyclic molecular graphs with presbribed girth and minimal Hosoya index[J].J Math Chem,2007,42(3):423-432.

Gutman I.Maxima and Minima of Hosoya Inedx and the Merrifield-Simmoms Inedx[J].Acta Appl Math,2010,112(3):323-346.