KALITA, E. A. Exactness of the cordes condition of the Hölder property for the gradient of nondivergent elliptic systems. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 47, n. 2, p. 292–294, 1995. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5415. Acesso em: 7 apr. 2025.