TY  - RPRT
TI  - Spirit leveling in Illinois, 1896-1942. Part 1, Southern Illinois
AU  - Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey
PY  - 1942
DO  - 10.3133/b930a
UR  - https://pubs.usgs.gov/publication/b930A
ID  - b930A
ER  -