Elserra Siemin Ciamas. “Komponen Biaya Promosi Dari Marketing Mix Terhadap Volume Penjualan Jasa Tur Dan Travel Di Medan”. Journal of Trends Economics and Accounting Research 3, no. 4 (June 30, 2023). Accessed May 12, 2026. https://journal.fkpt.org/index.php/jtear/article/view/627.