APA (7th ed.) Citation

Helgesen, J. O., Leonard, R. B., & Wolf, R. J. (1993). Hydrology of the Great Plains aquifer system in Nebraska, Colorado, Kansas, and adjacent areas. U.S. Department of the Interior, U.S. Geological Survey.

Chicago Style (17th ed.) Citation

Helgesen, John O., Robert B. Leonard, and R. J. Wolf. Hydrology of the Great Plains Aquifer System in Nebraska, Colorado, Kansas, and Adjacent Areas. Washington: U.S. Department of the Interior, U.S. Geological Survey, 1993.

MLA (9th ed.) Citation

Helgesen, John O., et al. Hydrology of the Great Plains Aquifer System in Nebraska, Colorado, Kansas, and Adjacent Areas. U.S. Department of the Interior, U.S. Geological Survey, 1993.