@article{D._Knez_Looking_2018, author={D. Knez and Calicki, A.}, volume={66}, number={No 1}, howpublished={online}, journal={Bulletin of the Polish Academy of Sciences: Technical Sciences}, pages={3-8}, year={2018}, title={Looking for a new source of natural proppants in Poland}, type={Artykuły / Articles}, doi={10.24425/119052}, keywords={proppant, mechanical properties, hydraulic fracturing}, }