TY  - RPRT
TI  - Big Snowy and Amsden groups and the Mississippian-Pennsylvanian boundary in Montana
AU  - E. K. Maughan
AU  - A. E. Roberts
PY  - 1967
DO  - 10.3133/pp554b
UR  - https://pubs.usgs.gov/publication/pp554B
ID  - pp554B
ER  -