Hidayatullah Elmas, M. S., H. Hermanto, A. Yatiningrum, N. Rosita, and E. Rianti. “Pengaruh Dimensi Bauran Promosi Terhadap Keputusan Pembelian Kartu Perdana Telkomsel”. Jurnal Ilmiah Ecobuss, Vol. 6, no. 1, Mar. 2018, pp. 39 -51, https://ejournal.upm.ac.id/index.php/ecobuss/article/view/262.