W. B. Ginting, D. S. Sari, and E. Lubis, “Development Strategy Of Cv Zahra’s Mononitrate Oil Umkm Through Digital Marketing In Sumbu Berastagi Village, Karo Regency”, J. Manag. Econ. Account., vol. 5, no. 2, pp. 1111–1116, Apr. 2026.