PURBA, Michael Jordan. Williamson, G.I. Katekismus Heidelberg: Sebuah Panduan Studi. Diligentia: Journal of Theology and Christian Education, [S. l.], v. 2, n. 1, p. 120–121, 2020. DOI: 10.19166/dil.v2i1.2207. Disponível em: https://ojs.uph.edu/index.php/DIL/article/view/2207. Acesso em: 20 nov. 2025.