Income tax return form (1040A), 1922; Farm account book, 1926; Producers Commission Association handbook with picture of Cottrell, 1922 - 1928, Box: 1, Folder: 6. John Cottrell papers, RH MS 1315. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/152883 Accessed June 14, 2025.