Marchenko, V. A. (2013). Symmetrically-spectral operators on $\ell_p$ $(1\leq p< \infty)$ and $c_0$ spaces. Visnyk of V. N. Karazin Kharkiv National University. Ser. Mathematics, Applied Mathematics and Mechanics, (1081), 33-44. https://doi.org/10.26565/2221-5646-2013-1081-04