APA (7th ed.) Citation

Illinois State Geological Survey, Illinois. Department of Registration and Education, & McGinnis, L. D. (1976). The Gravity field and tectonics of Illinois. Illinois State Geological Survey.

Chicago Style (17th ed.) Citation

Illinois State Geological Survey, Illinois. Department of Registration and Education, and Lyle David McGinnis. The Gravity Field and Tectonics of Illinois. Urbana: Illinois State Geological Survey, 1976.

MLA (9th ed.) Citation

Illinois State Geological Survey, et al. The Gravity Field and Tectonics of Illinois. Illinois State Geological Survey, 1976.