GAŁKA, A.; GAMBIN, B.; TELEGA, J.J. Variational bounds on the effective moduli of anisotropic piezoelectric composites. Archives of Mechanics, Warsaw, Poland, v. 50, n. 4, p. 675–689, 1998. Disponível em: http://am.ippt.gov.pl/index.php/am/article/view/v50p675. Acesso em: 17 jan. 2026.