Tran, N. K., T. Q. A. Tran, T. D. Nguyen, and D. M. Le. “Studying the Affected Factors to Freeze Drying Process of Natto Preparation”. Journal of Technical Education Science, vol. 11, no. Special Issue 02, Dec. 2016, pp. 1-10, https://www.jte.edu.vn/index.php/jte/article/view/405.