APA (7th ed.) Citation

Grass, L. B., MacKenzie, A. J., & Willardson, L. S. Inspecting and cleaning subsurface drain systems (Slightly rev. Sept. 1976.).

Chicago Style (17th ed.) Citation

Grass, L. B., A. J. MacKenzie, and Lyman S. Willardson. Inspecting and Cleaning Subsurface Drain Systems. Slightly rev. Sept. 1976.

MLA (9th ed.) Citation

Grass, L. B., et al. Inspecting and Cleaning Subsurface Drain Systems. Slightly rev. Sept. 1976.