Liu, L., He, A. and Li, X. (2012) “Synthesis of Allantoin Catalyzed by SO42-/La2O3-SiO2-ZrO2”, Asian Journal of Chemistry, 24(5), pp. 2298–2300. Available at: https://asianpubs.org/index.php/ajchem/article/view/9004 (Accessed: 24 June 2024).