APA (7th ed.) Citation

Geological Survey (U.S.) & Scott, G. R. (1989). Historic trail maps of the Sterling 1?x 2?quadrangle, northeastern Colorado. The Survey.

Chicago Style (17th ed.) Citation

Geological Survey (U.S.) and Glenn R. Scott. Historic Trail Maps of the Sterling 1?x 2?quadrangle, Northeastern Colorado. Reston, Va.: The Survey, 1989.

MLA (9th ed.) Citation

Geological Survey (U.S.) and Glenn R. Scott. Historic Trail Maps of the Sterling 1?x 2?quadrangle, Northeastern Colorado. The Survey, 1989.