"January 1980 37379-2. June 1979 Base 4-R-37110-2." "Base compiled from latest USGS quad sheets." Includes location maps. Available also through the Library of Congress Web site as a raster image.
United States. Soil Conservation Service
1980
<a rel="nofollow" class="external free" href="https://www.loc.gov/item/82692935/">https://www.loc.gov/item/82692935/</a>