"Imperial Valley South Access Guide" (Imperial Valley, CA: Produced by The U.S. Department of the Interior), undated, Sub-Series 1.2, Box: 3, Folder: 2. Collection of California maps and guidebooks, SC-012. Pfau Library Special Collections. https://archivesspace.csusb.edu//repositories/3/archival_objects/6714 Accessed November 15, 2024.