Cita APA (7th ed.)

United States. National Park Service. (1968). Explorers and settlers: Historic places commemorating the early exploration and settlement of the United States. [s. n.].

Cita Chicago (17th ed.)

United States. National Park Service. Explorers and Settlers: Historic Places Commemorating the Early Exploration and Settlement of the United States. Washington, D. C: [s. n.], 1968.

Cita MLA (9th ed.)

United States. National Park Service. Explorers and Settlers: Historic Places Commemorating the Early Exploration and Settlement of the United States. [s. n.], 1968.