Ratsimbanierana, Hermann, Sara Sbai, and Agathe Stenger. “Moroccan Tourist Portfolio Efficiency With the Mean-Variance Approach”. European Journal of Tourism Research 6, no. 2 (October 1, 2013): 122–131. Accessed November 12, 2026. https://www.ejtr.vumk.eu/index.php/about/article/view/126.