Montazeri, N., et al. “Synthesis of 1,2,4-Triazolo[5,1-b][1,3]-Thiazin-7-Ones Catalyzed by Pentafluorophenylammonium Triflate”. Asian Journal of Chemistry, vol. 24, no. 6, Feb. 2012, pp. 2802-4, https://asianpubs.org/index.php/ajchem/article/view/9229.