Bush, A L., & Hayes, T S. (1995). Industrial minerals of the midcontinent: Proceedings of the Midcontinent Industrial Minerals Workshop. Washington: United States Gov. Print. Office.

Industrial minerals of the midcontinent : Proceedings of the Midcontinent Industrial Minerals Workshop / ed. and comp. by Alfred L. Bush .. . — Washington : United States Gov. Print. Office, 1995. — IX, 126 S.; Ill., graph. Darst., Kt. — (US Geological Survey bulletin ; 2111)

Bush, Alfred L., and Timothy Scott Hayes. Industrial Minerals of the Midcontinent: Proceedings of the Midcontinent Industrial Minerals Workshop.Washington: United States Gov. Print. Office, 1995.