Das Sarma, Madhushree, and Subhojit Ghosh. “Recent Advances in Catalysis of Hantzsch and Related Synthesis of 1,4-Dihydropyridines and Polyhydroquinolines: A Brief Overview”. Asian Journal of Chemistry, vol. 32, no. 12, Dec. 2020, pp. 2943-52, doi:10.14233/ajchem.2020.22955.