Bulletin of the American Geographical Society. American Geographical Society.
Style de citation Chicago (17e éd.)Bulletin of the American Geographical Society. American Geographical Society.
Style de citation MLA (8e éd.)Bulletin of the American Geographical Society. American Geographical Society.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.