Peng, H.-N., Peng, X.-M., & Zheng, D.-G. (2010). p-Toluene Sulfonic Acid Catalyzed One-Pot Synthesis of Unsymmetrical 1,4-Dihydropyridines Derivatives via Hantzsch Reaction. Asian Journal of Chemistry, 23(4), 1833–1837. Retrieved from https://asianpubs.org/index.php/ajchem/article/view/10267