Bulkis, Iin, et al. “The EFL Teachers’ Implementation of 6C Skills (Critical Thinking, Creativity, Collaboration, Communication, Citizenship, and Character) of 21st Century Skills”. EduLine: Journal of Education and Learning Innovation, vol. 5, no. 2, May 2025, pp. 262-73, doi:10.35877/454RI.eduline3927.