Ahmadi, Ahmadi, et al. “The Internalization of Attitude and Values: Comparison Study in PTKIN and PTKIS”. Cendekia: Jurnal Kependidikan Dan Kemasyarakatan, vol. 18, no. 1, May 2020, pp. 17-32, https://jurnal.iainponorogo.ac.id/index.php/cendekia/article/view/1761.