APA (7th ed.) Citation

Hoar, H. M. (1930). Coal industry of world, with special reference to international trade in coal. U.S. Government Printing Office.

Chicago Style (17th ed.) Citation

Hoar, H. M. Coal Industry of World, with Special Reference to International Trade in Coal. [Washington?]: U.S. Government Printing Office, 1930.

MLA (9th ed.) Citation

Hoar, H. M. Coal Industry of World, with Special Reference to International Trade in Coal. U.S. Government Printing Office, 1930.