Syarifah, Desinora Natalia Hutauruk, Diancrisy Situmeang, Maria Innest, and Siti Nurhidayah Al-Anshari, “Biography of Willem Iskandar and his role in education In North Sumatra: Biografi Willem Iskandar Dan Perannya Dalam Pendidikan Di Sumatera Utara”, JS, vol. 8, no. 1, pp. 402-407, Apr. 2024.