C. . Siahaan, D. N. . Sihaloho, A. W. . Daulat Lumbangaol, and C. A. Limbong, “Improving Students Ability in Writing Descriptive Text Through Self-Directed Learning for Eight rade at SMP N 9 Pematangsiantar”, jptam, vol. 7, no. 1, pp. 2431–2437, Mar. 2023.