KHOLIS, Mukhammmad Nur. The Oral Communication in Teaching Speaking Using Problem Based Learning on Vocational School Students. RETAIN : Journal of Research in English Language Teaching, [S. l.], v. 9, n. 03, p. 184–191, 2022. Disponível em: https://ejournal.unesa.ac.id/index.php/retain/article/view/44036. Acesso em: 29 jun. 2025.