"The 1740 Description by Daniel Tilas of Stratigraphy and Petroleum Occurence at Osmundsberg in the Siljan Region of Central Sweden" by Hollis D. Hedberg, 1988, Box: 247, Folder: 35. Dean A. McGee papers, RH MS 537. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/157737 Accessed June 24, 2025.