LUKOVSKY, I. O.; TIMOKHA, A. N. Variational formulations of nonlinear boundary-value problems with a free boundary in the theory of interaction of surface waves with acoustic fields. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 45, n. 12, p. 1642–1652, 1993. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5972. Acesso em: 14 apr. 2025.