Higuchi et. al, "Asymmetric Oxidation of Thioethers to Sulfoxides. Configurational Specificity Induced by Optically Active Organic Catalysts,", 1966

Higuchi et. al, "Asymmetric Oxidation of Thioethers to Sulfoxides. Configurational Specificity Induced by Optically Active Organic Catalysts,", 1966, Box: 10, Folder: 47. Personal papers of Takeru Higuchi, PP 359. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/124471 Accessed December 25, 2025.