Não informado. (2021). Annual Bulletin of Coal Statistics for Europe and North America. United Nations.
Chicago-Zitierstil (17. Ausg.)Não informado. Annual Bulletin of Coal Statistics for Europe and North America. New York: United Nations, 2021.
MLA-Zitierstil (8. Ausg.)Não informado. Annual Bulletin of Coal Statistics for Europe and North America. United Nations, 2021.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.