R. El Sheikh, A. A. Gouda, and H. Soliman, “SENSITIVE SPECTROPHOTOMETRIC DETERMINATION OF ACETYLCHOLINESTRASE INHIBITOR DONEPEZIL HYDROCHLORIDE IN PURE FORM AND PHARMACEUTICAL FORMULATIONS USING SULPHONPHETHALIN DYES”, Int J Pharm Pharm Sci, vol. 8, no. 8, pp. 274–281, Aug. 2015.