Perles-Ribes, José, Luis Moreno Izquierdo, Aimée Penalva, and Ana Rodríguez. “Optimal Level of Tourism Specialization and the Mediating Role of Productivity”. European Journal of Tourism Research 42 (February 1, 2026): 4215. Accessed October 12, 2026. https://ejtr.vumk.eu/index.php/about/article/view/4102.