Liu, Hai (Jan 2018). "Explorations into Chinese as a second language". International Journal of Chinese Linguistics. 5: 167–170. doi:10.1075/ijchl.00003.liu. S2CID188412447.
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Liu, Hai (Jan 2018). "Explorations into Chinese as a second language". International Journal of Chinese Linguistics. 5: 167–170. doi:10.1075/ijchl.00003.liu. S2CID188412447.