"Paleontological Evidence of Variations in Length of Synodic Month Since Late Cambrian" Science, Nov. 15, 1968, Box: 9, Folder: 44. J. Harlan Johnson papers, RH MS 735. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/52950 Accessed April 18, 2025.