WORONOWICZ, Mateusz. A note on the square subgroups of decomposable torsion-free abelian groups of rank three. Annales Mathematicae Silesianae, [S. l.], v. 32, p. 319–331, 2017. Disponível em: https://journals.us.edu.pl/index.php/AMSIL/article/view/13930. Acesso em: 24 may. 2025.