Kindergarten Principles and Practice, Kate Douglas Wiggin and Nora Archibald Smith, (photocopies), 1898, Box: 5, Folder: 20. Personal Papers of Marguerite Baumgartel, PP 483. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/133835 Accessed May 17, 2024.