SITOHANG, Angelina -; SIREGAR, Masitowarni -. IMPROVING STUDENTS™ SPEAKING ACHIEVEMENT IN AGREEMENT AND DISAGREEMENT EXPRESSIONS BY USING PROBLEM SOLVING STRATEGY AT GRADE VIII SMP SWASTA HKBP SIDORAME MEDAN. TRANSFORM : Journal of English Language Teaching and Learning, North Sumatera, Indonesia, v. 3, n. 1, 2014. DOI: 10.24114/tj.v3i1.1819. Disponível em: https://jurnal.unimed.ac.id/2012/index.php/jelt/article/view/1819. Acesso em: 26 aug. 2025.