Okraj, Z. and Modrzejewska-Świgulska, M. (2019) “One theory – two research inspirations: A report from the research carried out with using theoretical and methodological approach of Howard E. Gruber”, Nauki o Wychowaniu. Studia Interdyscyplinarne, 7(2), pp. 159–182. doi: 10.18778/2450-4491.07.08.