Akmal Tarigan, A., N. Nurhayati, and M. Syukri Albani Nasution. “The Network of Ulama and Its Role in The Development of Islam in North Sumatra”. Religió Jurnal Studi Agama-Agama, vol. 10, no. 2, Sept. 2020, pp. 209-28, doi:10.15642/religio.v10i2.1337.