@misc{Wierzchowski_Krzysztof_Variability_2017,
 author={Wierzchowski, Krzysztof and Chećko, Jarosław and Pyka, Ireneusz},
 number={No 4},
 howpublished={online},
 year={2017},
 publisher={Committee of Mining PAS},
 title={Variability of Mercury Content in Coal Matter From Coal Seams of The Upper Silesia Coal Basin},
 doi={10.1515/amsc-2017-0058},
}