TY  - RPRT
TI  - Bibliography and index of U.S. Geological Survey publications relating to coal, 1882-1970
AU  - Paul Averitt
AU  - Lorreda Lopez
PY  - 1972
DO  - 10.3133/b1377
UR  - https://pubs.usgs.gov/publication/b1377
ID  - b1377
ER  -