First Day Stamp Smithsonian Institution Milestones In Flight John Glenn's First Orbital Flight, 1977-02-20, Box: 1, Folder: 15. Robbins Family Papers and Memorabilia, RH MS 1364. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/168799 Accessed May 19, 2024.