TY  - RPRT
TI  - Maps showing areal extent of selected Paleozoic shales in the northern Midcontinent, U.S.A.
AU  - W. P. Pratt
PY  - 1992
DO  - 10.3133/mf1835h
UR  - https://pubs.usgs.gov/publication/mf1835H
ID  - mf1835H
ER  -