KHARAKHANIAN, I. M. ON THE EQUATION ${\bf{\it h}}x-x{\bf{\it k}}=c$ IN BANACH ALGEBRA ${\bf{\it A}}$, WITH HERMITIAN COEFFICIENTS ${\bf{\it h}}, {\bf{\it k}}$. Proceedings of the YSU A: Physical and Mathematical Sciences, Yerevan, Armenia, v. 36, n. 1 (197), p. 3–8, 2002. DOI: 10.46991/PYSUA.2002.36.1.003. Disponível em: https://journals.ysu.am/index.php/proceedings-phys-math/article/view/vol36_no1_2002_pp003-008. Acesso em: 21 jan. 2026.