KLIMENKO, V. T. Approximation of functions of two variables by harmonic splines. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 47, n. 9, p. 1190–1196, 1995. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5518. Acesso em: 6 dec. 2025.