S. Kadirova and T. Lustina, “Regional differentiation of tour operator activity in Uzbekistan: comparative analysis of the tourism clusters of Samarkand, Bukhara and Khiva”, Сервис PLUS, vol. 20, no. 2, pp. 40–46, Mar. 2026, doi: 10.22412/2413-693X-2026-20-2-40-46.