PANGGABEAN, Waladdin. The Method of English Language Learning at Cambridge English Course Balikpapan. Jurnal Studi Guru dan Pembelajaran, [S. l.], v. 1, n. 1, p. 27–36, 2018. DOI: 10.30605/jsgp.1.1.2018.18. Disponível em: https://www.e-journal.my.id/jsgp/article/view/33. Acesso em: 7 jul. 2025.