PICHUGOV, S. A. Concave shells of continuity modules. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 71, n. 5, p. 716–720, 2019. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1470. Acesso em: 5 dec. 2025.