MELNIK , Yu. I. Approximation of functions regular in convex polyhedrons by exponential polynomials of a special form . Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 44, n. 3, p. 424–426, 1992. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8112. Acesso em: 5 dec. 2025.