See Soo Yin, and Arifuddin Abdullah. “LEARNERS’ ATTITUDES, PERCEPTIONS, AND EFFORTS TOWARDS MANDARIN AS A FOREIGN LANGUAGE COURSE”. Researchers World - International Refereed Social Sciences Journal, vol. 5, no. 4, Sept. 2021, pp. 38-47, https://www.researchersworld.com/index.php/rworld/article/view/825.