Munthe, K., and O. N. Ginting. “Effect of Quality of Service on Customer Satisfaction in Credit Union Cinta Kasih Tigapanah, Karo Regency, Indonesia”. The International Journal of Humanities & Social Studies, vol. 9, no. 1, Jan. 2021, doi:10.24940/theijhss/2021/v9/i1/HS2101-016.