Otto, Dr. David to President Richard Nixon, letter in support of Vietnam policy, May 9, 1972, Box: 1, Page: 129. 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/32522 Accessed June 13, 2024.