Bui, Quang Tuan, et al. “Practical Study of Purification of Lao Cai Wet Process Phosphoric Acid, Based on Tributyl Phosphate (TBP) – Kerosene Mixture Solvent Extraction”. Old Journal, no. 134A, June 2019, pp. 6-10, https://jst.vn/index.php/old/article/view/648.