Kelesbayev, Dinmukhamed, Kuatbek Kalykulov, Yermek Yertayev, Altynay Turlybekova, and Akhmet Kamalov. 2017. “Expressions Creating Confusion Among Elements of Promotion Mix: Sales Promotion”. International Review of Management and Marketing 7 (2):193-96. https://www.econjournals.com/index.php/irmm/article/view/3802.