BADRI, R., REZA KIASAT, A., & KESHAVARZ, M. (2010). Silica Phosphoric Acid as an Efficient Heterogeneous Catalyst for Protection of Carbonyl Groups Under Solvent Free Conditions. Asian Journal of Chemistry, 20(1), 543–546. Retrieved from https://asianpubs.org/index.php/ajchem/article/view/19441