APA (7th ed.) Citation

United Nations. Economic Commission for Europe. (1956). International classification of hard coals by type.

Chicago Style (17th ed.) Citation

United Nations. Economic Commission for Europe. International Classification of Hard Coals by Type. Geneva, 1956.

MLA (9th ed.) Citation

United Nations. Economic Commission for Europe. International Classification of Hard Coals by Type. 1956.

Warning: These citations may not always be 100% accurate.