Probierz, Krystian, and Marta Kwaśny. 2014. “Changes of Coal Rank and Petrographic Composition of Coals from the Drillhole BD 57 Deposit of "Bzie-Dębina" In the Jastrzębie Area (SW Part of the Upper Silesian Coal Basin)”. Geology, Geophysics and Environment 40 (1):66. https://doi.org/10.7494/geol.2014.39.1.66.