Hikmah, A., K. . Manurung, and A. K. . Dewi. “Developing Speaking Skill of Grade XI Students of SMA Negeri 1 Ampibabo through Problem Solving Method”. ELS Journal on Interdisciplinary Studies in Humanities, vol. 4, no. 4, Dec. 2021, pp. 413-2, doi:10.34050/elsjish.v4i4.18480.