Tavakoli-Hoseini, N., and A. Davoodnia. “Silica Gel-Supported Polyphosphoric Acid: A Mild, Efficient and Reusable Catalyst for the One-Pot Synthesis of 1,2,4,5-Tetrasubstituted Imidazoles”. Asian Journal of Chemistry 22, no. 9 (July 9, 2010): 7197–7200. Accessed July 4, 2024. https://asianpubs.org/index.php/ajchem/article/view/11968.