“Physico–Chemical Characterization of Vanadium–Phosphorus–Oxide Catalysts Prepared in Organic and Aqueous Medium”. Jurnal Teknologi (Sciences & Engineering) 34, no. 1 (January 20, 2012): 17–24. Accessed September 13, 2026. https://journals.utm.my/jurnalteknologi/article/view/637.