U.S. Dept. of the Interior, National Park Service,

National Park Service, U.S. Dept. of the Interior, Natural Resource Stewardship and Science,

U.S. National Park Service,

U.S. National Park Service

U.S. National Park Service

The Service,

United States Dept. of the Interior, National Park Service : [For sale by the Supt. of Docs., U.S. G.P.O.],

The Service,

National Park Service, Employees & Alumni Association],

The Service,

National Park Service

National Park Service, Dept. of the Interior,