TY  - RPRT
TI  - Coal petrographic laboratory procedures and safety manual II
AU  - J. Pontolillo
AU  - R.W. Stanton
PY  - 1994
DO  - 10.3133/ofr94631
UR  - https://pubs.usgs.gov/publication/ofr94631
ID  - ofr94631
ER  -