Rabanovych, V. I. “On Decompositions of a Scalar Operator into a Sum of Self-Adjoint Operators With Finite Spectrum”. Ukrains’kyi Matematychnyi Zhurnal 67, no. 5 (May 25, 2015): 701–716. Accessed April 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2016.