TY  - RPRT
TI  - Twenty-First Annual report of the Director of the United States Geological Survey, 1899-1900: Part VI - Mineral Resources of the United States, 1899, metallic products, coal, and coke
AU  - Charles D. Walcott
PY  - 1901
DO  - 10.3133/ar21_6
UR  - https://pubs.usgs.gov/publication/ar21_6
ID  - ar21_6
ER  -