Davoodnia, A. “H2SO4/Silica/Gel:/An/Efficient/and/Reusable/Heterogeneous/Catalyst/for/the/Synthesis/of/Pyrazolo[4,3-e][1,2,4]triazolo[4,3-c]pyrimidines”. Asian Journal of Chemistry 22, no. 2 (March 30, 2010): 1595–1598. Accessed July 1, 2024. https://asianpubs.org/index.php/ajchem/article/view/11300.