KIRIYATZKII, E. G.; KIRJACKIS, J. On Some Extremal Problems on Linearly Invariant Classes. Nonlinear Analysis: Modelling and Control, [S. l.], v. 10, n. 2, p. 161–170, 2005. DOI: 10.15388/NA.2005.10.2.15130. Disponível em: https://www.zurnalai.vu.lt/nonlinear-analysis/article/view/15130. Acesso em: 4 may. 2025.