APA (7th ed.) Citation

Geological Survey (U.S.), McLellan, M. W., & Olive, W. W. (1991). Geologic map of the Elk Ridge quadrangle, Powder River County, Montana. The Survey.

Chicago Style (17th ed.) Citation

Geological Survey (U.S.), Marguerite W. McLellan, and Wilds W. Olive. Geologic Map of the Elk Ridge Quadrangle, Powder River County, Montana. Reston, Va.: The Survey, 1991.

MLA (9th ed.) Citation

Geological Survey (U.S.), et al. Geologic Map of the Elk Ridge Quadrangle, Powder River County, Montana. The Survey, 1991.