Pfau, Christa, Éva Bartha, Éva Bácsné Bába, Réka Szabóné Szőke, and Anetta Müller. “Survey of the Service Offer of Fitness Clubs for Group Classes in Debrecen ”. International Journal of Engineering and Management Sciences 6, no. 2 (September 27, 2021): 35–48. Accessed April 28, 2024. https://ojs.lib.unideb.hu/IJEMS/article/view/9341.