@ARTICLE{
author={Gutman Ivan,Vidovic Dusica,Furtula Boris,Zenkevich IG},
year={2003},
title={Wiener-type indices and internal molecular energy},
journal={JOURNAL OF THE SERBIAN CHEMICAL SOCIETY},
volume={68},
number={4-5},
pages={401-408},
document_type={Article},
} 

@ARTICLE{
author={Gutman Ivan,Zenkevich IG},
year={2002},
title={Wiener index and vibrational energy},
journal={ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES},
volume={57},
number={9-10},
pages={824-828},
document_type={Article},
}