YOLA APRILIA SIBAGARIANG; KHAIRINA TAMBUNAN. Peran Customer Service (CS) Dalam Meningkatkan Loyalitas Nasabah Produk Tabungan Bank Sumut Cabang Syariah Sibolga. OPTIMAL Jurnal Ekonomi dan Manajemen, [S. l.], v. 4, n. 2, p. 198–207, 2024. DOI: 10.55606/optimal.v4i2.3476. Disponível em: https://journal.amikveteran.ac.id/index.php/optimal/article/view/3476. Acesso em: 3 jul. 2024.