"San Diego Zoo Official Guide Book" (San Diego, CA: Produced by the Zoological Society of San Diego), 1947, Sub-Series 2.4, Box: 18, Folder: 1. Collection of California maps and guidebooks, SC-012. Pfau Library Special Collections. https://archivesspace.csusb.edu//repositories/3/archival_objects/7144 Accessed November 15, 2024.