Kartini Rosmalah, and Shinta Agustianingrum. “The Effectiveness of Ruangguru Instagram Account Message As Digital Marketing Communication”. Jurnal Spektrum Komunikasi 9, no. 2 (December 27, 2021): 162–179. Accessed November 2, 2025. https://journal.stikosa-aws.ac.id/index.php/spektrum/article/view/124.