“Colorimetric Assay Of Naproxen Tablets by Derivatization Using 4-Carboxyl-2,6-Dinitrobenzene Diazonium Ion”. 2018. The East and Central African Journal of Pharmaceutical Sciences 12 (1): 8-14. http://jsep.uonbi.ac.ke/ojs/index.php/ecajps/article/view/85.