TY  - RPRT
TI  - The U.S. Geological Survey coal quality (COALQUAL) database version 3.0
AU  - Curtis A. Palmer
AU  - Charles L. Oman
AU  - Andy J. Park
AU  - James A. Luppens
PY  - 2015
DO  - 10.3133/ds975
UR  - https://pubs.usgs.gov/publication/ds975
ID  - ds975
ER  -