GRĄDZKA, E. A companion to Kazimierz Twardowski. Philosophical Problems in Science (Zagadnienia Filozoficzne w Nauce), [S. l.], n. 72, p. 191–202, 2022. Disponível em: https://zfn.edu.pl/index.php/zfn/article/view/586. Acesso em: 3 dec. 2022.