TY  - RPRT
TI  - Organic geochemistry of black shales, marlstones, and oils of Middle Pennsylvanian rocks from the northern Denver and southeastern Powder River basins, Wyoming, Nebraska, and Colorado
AU  - J.L. Clayton
AU  - Augusta Warden
AU  - T.A. Daws
AU  - P. G. Lillis
AU  - G.E. Michael
AU  - M. Dawson
PY  - 1992
DO  - 10.3133/b1917k
UR  - https://pubs.usgs.gov/publication/b1917K
ID  - b1917K
ER  -