Lei, Yingjie, Mei Ding, and Qingjia Yao. “An Efficient One-Pot Synthesis of 4-Methyl Coumarins Mediated by Melamine Formaldehyde Resin Supported Sulfuric Acid”. Asian Journal of Organic & Medicinal Chemistry 2, no. 3 (September 29, 2017): 110–113. Accessed May 19, 2024. https://asianpubs.org/index.php/ajomc/article/view/15461.