@ARTICLE{
author={Doslic Tomislav,Furtula Boris,Graovac Ante,Gutman Ivan,Moradi Sirous,Yarahmadi Zahra},
year={2011},
title={On Vertex-Degree-Based Molecular Structure Descriptors},
journal={MATCH-COMMUNICATIONS IN MATHEMATICAL AND IN COMPUTER CHEMISTRY},
volume={66},
number={2},
pages={613-626},
document_type={Article},
} 

@ARTICLE{
author={Yarahmadi Zahra,Ashrafi Ali Reza,Gutman Ivan},
year={2011},
title={First and second extremal bipartite graphs with respect to PI index},
journal={MATHEMATICAL AND COMPUTER MODELLING},
volume={54},
number={9-10},
pages={2460-2463},
document_type={Article},
}