APA (7th ed.) Citation

Harris, S. E., Horrell, C. W., & Irwin, D. (1977). Exploring the land and rocks of southern Illinois: A geological guide. Southern Illinois University Press.

Chicago Style (17th ed.) Citation

Harris, Stanley Edwards, C. William Horrell, and Daniel Irwin. Exploring the Land and Rocks of Southern Illinois: A Geological Guide. Carbondale: Southern Illinois University Press, 1977.

MLA (9th ed.) Citation

Harris, Stanley Edwards, et al. Exploring the Land and Rocks of Southern Illinois: A Geological Guide. Southern Illinois University Press, 1977.