D. D. S. Saragi and L. Saragih, “Peranan Sales Promotion Representative Terhadap Volume Penjualan Shinzui Pada Pt. Focus Distribusi Nusantara”, Manajemen : Jurnal Ekonomi, vol. 1, no. 1, pp. 47–54, May 2019, doi: 10.36985/vxdwek32.