Hutagalung, Insenalia Sampe, and Lydia Purba. 2019. “ImprovingStudents’ Speaking Skills through Jigsaw at Grade Eleven of SMAKampus Nommensen Pematangsiantar”. Journal of English Teaching As a Foreign Language 5 (2):33-41. https://ejournal.uhn.ac.id/index.php/jetafl/article/view/122.