19. Pet. Pros. of the Deep Offshore. Negatives and Prints of Maps of Figs. 1-3 made at Triangle, Box: 83, Folder: 12. Hollis Hedberg papers, RH MS 546. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/151408 Accessed November 24, 2024.