Akter, Soniya, and Jianqing Song. “Problems in Pronunciation and Perception of Mandarin Tones: An Empirical Study on Bangladeshi Undergraduate Students in China”. Journal of Higher Education Theory and Practice 21, no. 16 (December 29, 2021). Accessed November 22, 2024. https://articlegateway.com/index.php/JHETP/article/view/4922.