TY  - RPRT
TI  - Superposed deposits of thick coal on the eastern edge of the Illinois Basin and their association with underlying geologic features
AU  - D. Harper
AU  - G.A. Olyphant
PY  - 1991
DO  - 10.1016/0166-5162(91)90035-h
UR  - https://pubs.usgs.gov/publication/70016692
ID  - 70016692
ER  -