TY  - RPRT
TI  - Exploration intensity map of the Upper Cretaceous Niobrara Formation, Denver Basin, Colorado, Nebraska and Wyoming
AU  - D.K. Higley
AU  - D. L. Gautier
AU  - R. F. Mast
PY  - 1987
DO  - 10.3133/ofr87351b
UR  - https://pubs.usgs.gov/publication/ofr87351B
ID  - ofr87351B
ER  -