صالح ز. (2007) “Methyl acetoacetate as a Coupling Agent inSpectrophotometric Determination of p- Aminobenzoic Acid by Azo-Dye Formation Reaction”, College of Basic Education Research Journal, 5(3), pp. 192–206. Available at: https://stats.uomosul.edu.iq/index.php/berj/article/view/39215 (Accessed: 26 October 2025).