TY  - RPRT
TI  - Exploration intensity map of the Upper Cretaceous Pierre Shale, Denver Basin, Colorado, Nebraska, and Wyoming
AU  - Debra K. Higley
AU  - D. L. Gautier
AU  - Richard F. Mast
PY  - 1987
DO  - 10.3133/ofr87351c
UR  - https://pubs.usgs.gov/publication/ofr87351C
ID  - ofr87351C
ER  -