1. Boersma, P., & Weenink, D. (2020). Praat: Doing Phonetics by Computer. https://www.fon.hum.uva.nl/praat/
2. Intonation
3. Cunningham, U. (2009). Phonetic Correlates of Unintelligibility in Vietnamese-Accented English. In Proceedings, Fonetik 2009. University of Stockholm.
4. EVALUATIVE REACTIONS TO ACCENTS
5. Hancock, M. (2003). English Pronunciation in Use. Cambridge University Press.