Abdelkader M, Harzellihala H, Aouatef A. Customer relationship management as a gateway to improve marketing performance of tourism agencies in the State of Biskra. IJEP [Internet]. 2025 Apr. 17 [cited 2025 Nov. 13];19(4):1431-53. Available from: http://ijeponline.org/index.php/journal/article/view/967