Wu, L., Yang, L., & Yan, F. (2010). Synthesis of 2,3-Dihydro-4-pyridones Using HClO4-SiO2 or NaHSO4-SiO2 as an Efficient Heterogeneous Catalyst. Asian Journal of Chemistry, 22(9), 6977–6982. Retrieved from https://asianpubs.org/index.php/ajchem/article/view/11937