ANASTASSIOU, George A. Self adjoint operator harmonic polynomials induced Chebyshev-Grüss inequalities. Studia Universitatis Babeș-Bolyai Mathematica, [S. l.], v. 62, n. 1, p. 39–56, 2017. DOI: 10.24193/subbmath.2017.0004. Disponível em: https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/1692. Acesso em: 5 feb. 2025.