"Mount Diablo California...Aeroplane View Scenic Boulevard" (Produced by Not Available), undated, Sub-Series 2.5, Box: 17, Folder: 1. Collection of California maps and guidebooks, SC-012. Pfau Library Special Collections. https://archivesspace.csusb.edu//repositories/3/archival_objects/7096 Accessed November 15, 2024.