TY  - RPRT
TI  - National coal resource assessment methodology; comparison of resource calculation methods by two Geographic Information Systems (GIS)
AU  - S.J. Tewalt
PY  - 1998
DO  - 10.3133/ofr98365
UR  - https://pubs.usgs.gov/publication/ofr98365
ID  - ofr98365
ER  -