Higuchi and Szulczewski, "Gas Chromatographic Separation of Some Permanent Gases on Silica Gel at Reduced Temperatures,", 1957, Box: 10, Folder: 145. Personal papers of Takeru Higuchi, PP 359. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/124569 Accessed May 25, 2024.