Majid, A. M. (2018). IMPROVING STUDENTS’ ABILITY IN EXPRESSING OPINION THROUGH GROUP INVESTIGATION AT THE STUDENTS CLASS XI IPA 1 SEMESTER 1 SMA NEGERI 1 ABUNG SEMULI ACADEMIC YEAR 2016-2017. Edukasi Lingua Sastra, 16(1), 110–117. https://doi.org/10.47637/elsa.v16i1.82