Williny, Rina Friska B Siahaan, and Elserra Siemin Ciamas. “Markov Analysis: Strategi Mempertahankan Brand Image Produk Unggulan Sumatera Utara”. Jurnal E-Bis 5, no. 1 (June 11, 2021): 287-295. Accessed May 2, 2026. https://jurnal.politeknik-kebumen.ac.id/E-Bis/article/view/774.