APA-Zitierstil (7. Ausg.)

(1982). Ecoregion, land-surface form and hydrologic unit maps of the United States. U.S. Fish and Wildlife Service.

Chicago-Zitierstil (17. Ausg.)

Ecoregion, Land-surface Form and Hydrologic Unit Maps of the United States. Kearneysville, West Virginia: U.S. Fish and Wildlife Service, 1982.

MLA-Zitierstil (9. Ausg.)

Ecoregion, Land-surface Form and Hydrologic Unit Maps of the United States. U.S. Fish and Wildlife Service, 1982.