APA (7th ed.) Citation

Duwelius, R. F., & Silcox, C. A. (1991). Ground-water levels, flow, and quality in northwestern Elkhart County, Indiana, 1980-89. U.S. Geological Survey.

Chicago Style (17th ed.) Citation

Duwelius, Richard F., and Cheryl A. Silcox. Ground-water Levels, Flow, and Quality in Northwestern Elkhart County, Indiana, 1980-89. Indianapolis, Indiana: U.S. Geological Survey, 1991.

MLA (9th ed.) Citation

Duwelius, Richard F., and Cheryl A. Silcox. Ground-water Levels, Flow, and Quality in Northwestern Elkhart County, Indiana, 1980-89. U.S. Geological Survey, 1991.