Pumpelly, R., & Willis, B. (1886). Report on the mining industries of the United States (exclusive of the precious metals): With special investigation into the iron resources of the republic and into the Cretaceous coals of the Northwest. Govt.Print. Off..
Trích dẫn kiểu Chicago (xuất bản lần thứ 7)Pumpelly, Raphael, và Bailey Willis. Report on the Mining Industries of the United States (exclusive of the Precious Metals): With Special Investigation into the Iron Resources of the Republic and into the Cretaceous Coals of the Northwest. Washington: Govt.Print. Off., 1886.
Trích dẫn kiểu MLA (xuất bản lần thứ 8)Pumpelly, Raphael, và Bailey Willis. Report on the Mining Industries of the United States (exclusive of the Precious Metals): With Special Investigation into the Iron Resources of the Republic and into the Cretaceous Coals of the Northwest. Govt.Print. Off., 1886.