1993. 2007-04-18T14:25:50Z. 2011-06-03T19:38:14Z. Hildenbrand, T. G. Dept. of Energy and Natural Resources, Illinois State Geological Survey. English. Public. Illinois.
1995. 2011-11-16T21:06:52Z. 2015-10-21T15:08:13Z. U.S. Coast and Geodetic Survey. U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Ocean Service, Coast and Geodetic Survey. English. Public. Illinois, Chicago, and Michigan, Lake.
1999. 2011-11-16T21:12:38Z. 2015-10-21T15:05:57Z. United States Coast Survey. The Survey ; NOAA Distribution Division, N/ACC3, National Ocean Service, distributor. English. Public. Illinois, Chicago, Indiana Harbor (East Chicago, Ind.), and Michigan, Lake.
1995. 2011-11-16T21:04:52Z. 2015-10-21T15:08:13Z. U.S. Coast and Geodetic Survey. U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Ocean Service, Coast and Geodetic Survey. English. Public. Illinois, Chicago, Indiana, and Michigan, Lake.