Febriani, R., E. Bunau, Surmiyati, Y. Gatot Sutapa Yuliana, and U. Salam. “Improving Student’s English Vocabulary Using Duolingo Application”. Journal of Scientific Research, Education, and Technology (JSRET), vol. 2, no. 4, Dec. 2023, pp. 1789-9, doi:10.58526/jsret.v2i4.297.