Não informado. Topographic instructions of the United States Geological Survey. U.S. Department of the Interior.
Style de citation Chicago (17e éd.)Não informado. Topographic Instructions of the United States Geological Survey. Washington: U.S. Department of the Interior.
Style de citation MLA (8e éd.)Não informado. Topographic Instructions of the United States Geological Survey. U.S. Department of the Interior.
Attention : ces citations peuvent ne pas être correctes à 100%.