LUBIS, R. H.; MANULLANG, A. A.; MALAU, C. K.; PASARIBU, M. D. S.; SITUMORANG, S. MEMBANGUN KETERAMPILAN ABAD 21: REVIEW LITERATUR TENTANG EFEKTIVITAS MODEL PEMBELAJARAN PROBLEM-BASED LEARNING (Building 21st Century Skills: A Literature Review on the Effectiveness of Problem-Based Learning Learning Models). Sindoro: Cendikia Pendidikan, [S. l.], v. 9, n. 1, p. 11–20, 2024. DOI: 10.9644/sindoro.v9i1.7637. Disponível em: https://ejournal.warunayama.org/index.php/sindorocendikiapendidikan/article/view/7637. Acesso em: 22 aug. 2025.