Letters from David Keene, Kent Crane and J. Marsh Thompson to Dr. David A. Otto regarding meetings, April 9, 20, 22, 1971, Box: 1, Page: 111-113. The Dr. David A. Otto, Special Envoy for the Missouri State Teachers Association during the time of the 1971 Paris Peace Talks, collection, RH MS 1257. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/32516 Accessed June 01, 2024.