GOLOSHCHAPOVA, N.; ANANIEVA, A. On the extremal extensions of a non-negative Jacobi operator. Methods of Functional Analysis and Topology, [S. l.], v. 19, n. 4, p. 310–318, 2013. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/555. Acesso em: 4 feb. 2026.