Sagala, Poster, Lina Tarigan, Immanuel Padang, and Dorayanti Lumbangaol. “Workshop of Improving Teachers’ Competency in Teaching Speaking by Using Buzz Group at SMA Kristen Kalam Kudus Medan”. JURNAL ABDIMAS MADUMA 1, no. 1 (March 10, 2022): 77–88. Accessed April 19, 2026. https://journal.eltaorganization.org/index.php/ecdj/article/view/100.