"The Stratigraphic Panorama," Hollis D. Hedberg. Geological Society of America bulletin v. 72 p. 499-518, April 1961, Box: 10, Folder: 31. Hollis Hedberg papers, RH MS 546. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/149253 Accessed November 28, 2024.