Letter to the Fairmount Park Commission from John Samuel, Secretary of the Zoological Society, requesting an extension of lease so as to include the ground on the east side of 35th Street and between the north and south boundaries of the Zoological Garden, 1875 January 15, Drawer: 5-5. History Files, FP.2010.001.006. Fairmount Park Historic Resources Archive. https://pprarchives.libraryhost.com/repositories/2/archival_objects/405755 Accessed April 20, 2025.