TY  - RPRT
TI  - Twentieth Annual report of the United States Geological Survey, 1898-1899: Part VI - Mineral resources of the United States 1898, Metallic Products, Coal, and Coke
AU  - Charles D. Walcott
PY  - 1899
DO  - 10.3133/ar20_6
UR  - https://pubs.usgs.gov/publication/ar20_6
ID  - ar20_6
ER  -