1. D 388 – 99: Standard Classification of Coals by Rank,1999
2. Coke in the iron and steel industry;Babich,2019
3. International legal aspects of the Russian Federation's aggression against Ukraine, justice and mechanisms of counteraction and legal liability for the war crimes and genocide;Bilas;Ad Alta – J. Interdiscip. Res.,2022
4. Czechoslovak National Standard: Classification of Fossil Solid Fuels; Approved in June 22, 1960, Active since February 1, 1961; Úřad Pro Normalizaci a Měření: Praha,1960
5. Czechoslovak National Standard: Classification of Hard Coals by Code Numbers. Approved in December 21, 1966, Active since October 1, 1967; Úřad Pro Normalizaci a Měření: Praha,1969