@ARTICLE{
author={Petrovic Jelica M,Ivkovic Ivan S,Vujacic Ivan,Zezelj Srecko},
year={2009},
title={Possibilities of Buses on Alternative Fuel in Public Urban Transport in Belgrade},
journal={TECHNOLOGICAL AND ECONOMIC DEVELOPMENT OF ECONOMY},
volume={15},
number={1},
pages={78-89},
document_type={Article},
} 

@ARTICLE{
author={Petrovic Jelica M,Ivkovic Ivan S,Vujacic Ivan,Zezelj Srecko},
year={2008},
title={Environmental and economic effects of natural gas and biodiesel buses in public urban transport - the case of Belgrade},
journal={7TH INTERNATIONAL CONFERENCE ENVIRONMENTAL ENGINEERING, VOLS 1-3},
volume={},
number={},
pages={1020-1026},
document_type={Proceedings Paper},
} 

@ARTICLE{
author={Petrovic Jelica M,Glumac Stanislav,Vujacic Ivan,Zezelj Srecko},
year={2001},
title={Effects of privatization of public urban transport - the case of Beograd},
journal={URBAN TRANSPORT VII: URBAN TRANSPORT AND THE ENVIRONMENT IN THE 21ST CENTURY},
volume={8},
number={},
pages={259-267},
document_type={Proceedings Paper},
}