APA (7th ed.) Citation

Hackett, J. E., & Bergstrom, R. E. (1956). Groundwater in northwestern Illinois. [publisher not identified].

Chicago Style (17th ed.) Citation

Hackett, James E., and Robert Edward Bergstrom. Groundwater in Northwestern Illinois. Urbana: [publisher not identified], 1956.

MLA (9th ed.) Citation

Hackett, James E., and Robert Edward Bergstrom. Groundwater in Northwestern Illinois. [publisher not identified], 1956.