صالح زينة. “Methyl Acetoacetate As a Coupling Agent InSpectrophotometric Determination of P- Aminobenzoic Acid by Azo-Dye Formation Reaction”. College of Basic Education Research Journal 5, no. 3 (August 1, 2007): 192–206. Accessed October 26, 2025. https://stats.uomosul.edu.iq/index.php/berj/article/view/39215.