Purwati, D., A. Mardhiah, E. Nurhasanah, and R. Ramli. “The Six Characteristics of Andragogy and Future Research Directions in EFL: A Literature Review”. Elsya : Journal of English Language Studies, Vol. 4, no. 1, Jan. 2022, pp. 86-95, doi:10.31849/elsya.v4i1.7473.