Hajipour, Abdol Reza, et al. “Brønsted Acidic Ionic Liquid As the Efficient and Reusable Catalyst for Synthesis of Coumarins via Pechmann Condensation under Solvent-Free Conditions”. Iranian Journal of Catalysis, vol. 5, no. 3, Feb. 2024, https://oiccpress.com/ijc/article/view/3856.