ST-22 Status of Stratigraphic Classification and Terminology. Paper pres. Berne, May 1967 (published IUGS 9/11/1967), Box: 35, Folder: 29. Hollis Hedberg papers, RH MS 546. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/150027 Accessed November 24, 2024.