Rao, L. Hanmanth, et al. “Synthesis and Characterisation of Critical Impurities in Ampicillin Trihydrate: N-Formyl Ampicilloic Acid and D-Phenylglycylampicillin”. Asian Journal of Chemistry, vol. 38, no. 2, Jan. 2026, pp. 517-21, doi:10.14233/ajchem.2026.35101.