TY  - RPRT
TI  - Preliminary map of lead provinces in the conterminous United States
AU  - Edwin Wilson Tooker
AU  - H. T. Morris
PY  - 1980
DO  - 10.3133/ofr79576p
UR  - https://pubs.usgs.gov/publication/ofr79576P
ID  - ofr79576P
ER  -