@ARTICLE{
author={Zivotic Dragana R,Bechtel Achim,Sachsenhofer Reinhard F,Gratzer Rainhard,Radic Dejan B,Obradovic Marko O,Stojanovic Ksenija A},
year={2015},
title={Petrological and organic geochemical properties of lignite from the Kolubara and Kostolac basins, Serbia: Implication on Grindability Index (Reprinted)},
journal={INTERNATIONAL JOURNAL OF COAL GEOLOGY},
volume={139},
number={},
pages={165-183},
document_type={Reprint},
} 

@ARTICLE{
author={Zivotic Dragana R,Bechtel Achim,Sachsenhofer Reinhard F,Gratzer Rainhard,Radic Dejan B,Obradovic Marko O,Stojanovic Ksenija A},
year={2014},
title={Petrological and organic geochemical properties of lignite from the Kolubara and Kostolac basins, Serbia: Implication on Grindability Index},
journal={INTERNATIONAL JOURNAL OF COAL GEOLOGY},
volume={131},
number={},
pages={344-362},
document_type={Article},
}