Higuchi et. al, "Amino Acid Esters of Phenols as Prodrugs: Synthesis and Stability of Glycine, -Aspartic Acid, and -Aspartic Acid Esters of -Acetamidophenol,", 1981

Higuchi et. al, "Amino Acid Esters of Phenols as Prodrugs: Synthesis and Stability of Glycine, β-Aspartic Acid, and α-Aspartic Acid Esters of p-Acetamidophenol,", 1981, Box: 10, Folder: 39. Personal papers of Takeru Higuchi, PP 359. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/124463 Accessed December 25, 2025.