G.S. · Geological Survey · S. G. · S S
Cornell University Library · Nabu Press
| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Bulletin - Illinois State Geological Survey, Issue 5 | 978-1-145-61695-0 (1-145-61695-X) | 2010 |
| Bulletin - State of Illinois, State Geological Survey, Issue 35 | 978-1-145-63348-3 (1-145-63348-X) | 2010 |
| Directory of Illinois Mineral Operators, to Accompany Mineral Industries Map, September 1, 1920: Comp. By H. P. Christensen | 978-1-112-51403-6 (1-112-51403-1) | 2009 |