Tinambunan, Erbin -, dan Siti Aisah Ginting. “NATURAL APPROACH”. TRANSFORM: Journal of English Language Teaching and Learning 3, no. 4 (Desember 15, 2014). Diakses September 30, 2026. https://jurnal.unimed.ac.id/2012/index.php/jelt/article/view/1844.