APA (7th ed.) Citation

Sellards & Grigg, Inc, & United States. National Park Service. (1991). Staple Bend Tunnel: Allegheny Portage Railroad National Historic Site. U.S. Dept. of the Interior, National Park Service.

Chicago Style (17th ed.) Citation

Sellards & Grigg, Inc, and United States. National Park Service. Staple Bend Tunnel: Allegheny Portage Railroad National Historic Site. [Washington, D.C.?]: U.S. Dept. of the Interior, National Park Service, 1991.

MLA (9th ed.) Citation

Sellards & Grigg, Inc, and United States. National Park Service. Staple Bend Tunnel: Allegheny Portage Railroad National Historic Site. U.S. Dept. of the Interior, National Park Service, 1991.