Cai, Yan-Hua, et al. “Synthesis of Schiff Base Derived from P-Aminobenzoic Acid by Solvent-Free Reaction Using Jet Milling”. Asian Journal of Chemistry, vol. 22, no. 8, June 2010, pp. 5835-40, https://asianpubs.org/index.php/ajchem/article/view/11780.