TY  - RPRT
TI  - Recommended procedures and techniques for the petrographic description of bituminous coals
AU  - E. C. T. Chao
AU  - J.A. Minkin
AU  - C.L. Thompson
PY  - 1982
DO  - 10.1016/0166-5162(82)90003-9
UR  - https://pubs.usgs.gov/publication/70011503
ID  - 70011503
ER  -