APA (7th ed.) Citation

Hopkins, M. E. (1968). Harrisburg (no. 5) coal reserves of southeastern Illinois. Illinois State Geological Survey.

Chicago Style (17th ed.) Citation

Hopkins, M. E. Harrisburg (no. 5) Coal Reserves of Southeastern Illinois. Urbana: Illinois State Geological Survey, 1968.

MLA (9th ed.) Citation

Hopkins, M. E. Harrisburg (no. 5) Coal Reserves of Southeastern Illinois. Illinois State Geological Survey, 1968.