LIGUN, A. A.; SHUMEIKO, A. A. On one problem of minimization of area. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 7, p. 927–936, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5083. Acesso em: 5 dec. 2025.