APA (7th ed.) Citation

Illinois State Geological Survey & Illinois. Dept. of Registration and Education. Circular - Illinois State Geological Survey. Illinois State Geological Survey.

Chicago Style (17th ed.) Citation

Illinois State Geological Survey and Illinois. Dept. of Registration and Education. Circular - Illinois State Geological Survey. Urbana: Illinois State Geological Survey.

MLA (8th ed.) Citation

Illinois State Geological Survey and Illinois. Dept. of Registration and Education. Circular - Illinois State Geological Survey. Illinois State Geological Survey.

Warning: These citations may not always be 100% accurate.