Davoodnia, A., et al. “Eco-Friendly, Catalyst-Free Synthesis of 2-Amino-2-Chromenes in Ionic Liquid [bmim]Br”. Asian Journal of Chemistry, vol. 22, no. 10, Aug. 2010, pp. 7978-82, https://asianpubs.org/index.php/ajchem/article/view/12022.