BILICHENKO, R. O.; BABENKO, V. F. Refinement of a Hardy–Littlewood–Pólya-type inequality for powers of self-adjoint operators in a Hilbert space. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 61, n. 10, p. 1299–1305, 2009. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3101. Acesso em: 14 apr. 2025.