TY  - RPRT
TI  - Early Tertiary age of pitchstone in the northern Black Hills, South Dakota
AU  - J. A. Redden
AU  - J. D. Obradovich
AU  - C. W. Naeser
AU  - R. E. Zartman
AU  - J.J. Norton
PY  - 1983
DO  - 10.1126/science.220.4602.1153
UR  - https://pubs.usgs.gov/publication/70011208
ID  - 70011208
ER  -