KOVALEV , V. F.; MELNICHENKO , I. P. Biharmonic potentials and plane isotropic fields of displacement. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 40, n. 2, p. 229–231, 1988. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/9121. Acesso em: 7 dec. 2025.