Não informado. Topographic instructions of the United States Geological Survey. U.S. Department of the Interior.
Chicago-Zitierstil (17. Ausg.)Não informado. Topographic Instructions of the United States Geological Survey. Washington: U.S. Department of the Interior.
MLA-Zitierstil (8. Ausg.)Não informado. Topographic Instructions of the United States Geological Survey. U.S. Department of the Interior.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.