Narayanaswamy Venugopala, K., T. Prasanna, R., & Odhav, B. (2013). Trifluoroacetic Acid: An Efficient Catalyst for Paal-Knorr Pyrrole Synthesis and Its Deprotection. Asian Journal of Chemistry, 25(15), 8685–8689. https://doi.org/10.14233/ajchem.2013.15185