TY  - RPRT
TI  - Spirit leveling in Illinois, 1896-1942. Part 4, Northern Illinois
AU  - Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey
PY  - 1943
DO  - 10.3133/b930d
UR  - https://pubs.usgs.gov/publication/b930D
ID  - b930D
ER  -