“Colorimetric Assay Of Naproxen Tablets by Derivatization Using 4-Carboxyl-2,6-Dinitrobenzene Diazonium Ion”. The East and Central African Journal of Pharmaceutical Sciences, vol. 12, no. 1, Nov. 2018, pp. 8-14, http://jsep.uonbi.ac.ke/ojs/index.php/ecajps/article/view/85.