@ARTICLE{Miedzińska_D._Study_2013,
 author={Miedzińska, D. and Zasada, D. and Niezgoda, T. and Małek, E.},
 volume={61},
 number={No 2},
 journal={Bulletin of the Polish Academy of Sciences Technical Sciences},
 pages={499-505},
 howpublished={online},
 year={2013},
 title={Study on coal microstructure for porosity levels assessment},
 URL={http://journals.pan.pl/Content/83733/PDF/23_paper.pdf},
 doi={10.2478/bpasts-2013-0049},
}