KAŠUBA, Romualdas. Instructive problems of medium difficulty in math enviroments of Lithuania. Lietuvos matematikos rinkinys, [S. l.], v. 59, n. B, p. 20–26, 2018. DOI: 10.15388/LMR.B.2018.3. Disponível em: https://www.journals.vu.lt/LMR/article/view/14981.. Acesso em: 6 may. 2024.