El Sheikh, R., A. A. Gouda, and H. Soliman. “SENSITIVE SPECTROPHOTOMETRIC DETERMINATION OF ACETYLCHOLINESTRASE INHIBITOR DONEPEZIL HYDROCHLORIDE IN PURE FORM AND PHARMACEUTICAL FORMULATIONS USING SULPHONPHETHALIN DYES”. International Journal of Pharmacy and Pharmaceutical Sciences, vol. 8, no. 8, Aug. 2015, pp. 274-81, https://journals.innovareacademics.in/index.php/ijpps/article/view/6316.