Sinclair, Upton to Sir, includes notes on Sinclair's works and play "Cicero,", 1960, Box: 1, Folder: 17. Upton Sinclair Literary Manuscript and Correspondence, MS 299. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/238403 Accessed November 30, 2024.