@article{125099, recid = {125099}, author = {Berg, Richard C. and Kempton, John P.}, title = {Stack-unit mapping of geologic materials in Illinois to a depth of 15 meters /}, publisher = {Illinois State Geological Survey,}, address = {Champaign, Illinois :}, pages = {23 p. :}, year = {1988}, note = {Four maps on folded sheets in pocket.}, url = {http://library.usi.edu/record/125099}, }