Letter from [Count Karl Robert] Nesselrode, April 22, 1826 (St. Petersbourg [St. Petersburg]), Box: 22, Folder: 62. Letters, literary manuscripts, and personal papers of the Porter family, MS 28. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/467018 Accessed January 02, 2025.