Wu, Hui, Yu Wan, Ling Ye, and Leilei Lu. 2010. “One-Pot Synthesis of Triarylpyridines in Ionic Liquid and Their Catalyzed Active on a Simple Diels-Alder Reaction”. Asian Journal of Chemistry 21 (1):155-64. https://asianpubs.org/index.php/ajchem/article/view/18908.