Purba, Daniel Rizki, et al. “Oikumenitas Dan Solidaritas Ciptaan Allah Menurut Dokumen Teologi Gereja HKBP [Ecumenism and Solidarity of God’s Creation According to the HKBP Church Theological Document]”. Diligentia: Journal of Theology and Christian Education, vol. 6, no. 2, May 2024, pp. 173-88, doi:10.19166/dil.v6i2.8161.