TY - RPRT TI - Principal facts and complete Bouguer gravity anomaly map for the west half of the Butte 1° x 2 ° quadrangle, Montana AU - Jerry H. Hassemer PY - 1981 DO - 10.3133/ofr81949 UR - https://pubs.usgs.gov/publication/ofr81949 ID - ofr81949 ER -