TY  - RPRT
TI  - A modern vs. Permian black shale - the hydrography, primary productivity, and water-column chemistry of deposition
AU  - D.Z. Piper
AU  - R.B. Perkins
PY  - 2004
DO  - 10.1016/j.chemgeo.2003.12.006
UR  - https://pubs.usgs.gov/publication/70027040
ID  - 70027040
ER  -