Pennsylvania Railroad. (1876). The Centennial Exhibition and the Pennsylvania Railroad. The Company.
Chicago-referens (17:e uppl.)Pennsylvania Railroad. The Centennial Exhibition and the Pennsylvania Railroad. Philadelphia: The Company, 1876.
MLA-referens (8:e uppl.)Pennsylvania Railroad. The Centennial Exhibition and the Pennsylvania Railroad. The Company, 1876.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.