Tampubolon K, Sianturi CF, Hutabarat S. Pemberian Motivasi dan Pelatihan Operasi Hitung Aritmetika Sosial di Panti Asuhan Gratia Children Medan. ULEAD [Internet]. 2022Feb.15 [cited 2024Nov.21];1(2):94-105. Available from: https://ejournal.ust.ac.id/index.php/ULEAD/article/view/1719