ICS-12 Com. on the Silurian-Devonian Boundary and the Stratigraphy of the Lower and Middle Devonian, Box: 67, Folder: 6. Hollis Hedberg papers, RH MS 546. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/150946 Accessed June 24, 2025.