Kostyra, Agnieszka. “Kariera Dwutorowa: Sportowiec-Student I Sportowiec-Pracownik = Double Path Career: Sportsman-Student and Sportsman-Employee”. Journal of Education, Health and Sport, vol. 5, no. 7, June 2015, pp. 11-25, https://apcz.umk.pl/JEHS/article/view/2766.