Letter from [Count Karl Robert] Nesselrode, August 31, 1825 (St. Petersbourg [St. Petersburg]), Box: 22, Folder: 61. 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/467017 Accessed May 19, 2024.