Nguyen, Ngoc Thang, Duc Duong Pham, and Thi Lan Huong Vo. 2018. “Fabrication of a Visual PH Indicator Based on Cellulosic Materials and Anthocyanin Dyes Extracted from Red Cabbage”. Old Journal, no. 125 (April):71-75. https://jst.vn/index.php/old/article/view/824.