@ARTICLE{D._Knez_Looking_2018,
 author={D. Knez and Calicki, A.},
 volume={66},
 number={No 1},
 journal={Bulletin of the Polish Academy of Sciences Technical Sciences},
 pages={3-8},
 howpublished={online},
 year={2018},
 type={Artykuły / Articles},
 title={Looking for a new source of natural proppants in Poland},
 URL={http://www.czasopisma.pan.pl/Content/103595/PDF/003-008_00131_Bpast.No.66-1_28.02.18_K3.pdf},
 keywords={proppant, mechanical properties, hydraulic fracturing},
}