"Non-communist world demand and quality of petroleum requirement" by K. M. Elliott, J. G. Porter, and H. T. Kessler, 1963, Box: 20, Folder: 10. Charles Heller papers, RH MS 314. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/492914 Accessed February 26, 2025.