Michalska-Dudek, Izabela. “The Loyalty of Travel Agency Clients. An Empirical Study”. Regional Barometer. Analyses & Prognoses 16, no. 3 (December 18, 2018): 63–70. Accessed April 9, 2025. https://czaz.akademiazamojska.edu.pl/index.php/br/article/view/351.