Sinaga, Rosmaida, Ichwan Azhari, Lister Eva Simangunsong, and Pulung Sumantri. “Bongal Site of Central Tapanuli: Early Traces of the Spread of Christianity As a Learning Resource for History Subject in High Schools”. Journal Evaluation in Education (JEE) 6, no. 3 (July 29, 2025). Accessed August 2, 2025. https://cahaya-ic.com/index.php/JEE/article/view/1693.