“The Impact of Teacher Training on Student Achievement in English Teaching-Learning at SMA S Nupela”. Kopula: Jurnal Bahasa, Sastra, dan Pendidikan 7, no. 1 (Maret 28, 2025): 219–225. Diakses Oktober 16, 2025. https://jurnal.unram.ac.id/index.php/kopula/article/view/6292.