Enzmann, R.D. and J.M. 4th Conference on Planetology and Space Mission Planning. "Order Theory and Problems of Gravitation,", December 1972

Enzmann, R.D. and J.M. 4th Conference on Planetology and Space Mission Planning. "Order Theory and Problems of Gravitation,", December 1972, Box: 14a, Folder: 29. Papers of Theodore Sturgeon, MS 254. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/243974 Accessed December 25, 2025.