[1]
J. Grzelak, “The tourist activity of fitness trainers and participants of groups based on Lodz fitness clubs”, in Turystyka w badaniach podstawowych, vol. 13, M. Makowska-Iskierka and J. Wojciechowska, Eds. Poland: Lodz University Press, 2023. doi: 10.18778/8331-251-4.05.