Higuchi and Nakano, "Determination of Molecular Binding in Aqueous Solution from Optical Activity Measurements. Interaction of Tryptophan with Alkylxanthines,", 1968, Box: 10, Folder: 85. Personal papers of Takeru Higuchi, PP 359. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/124509 Accessed June 16, 2024.