CHŌ, Muneo, Eungil KO, and Ji Eun LEE. “Properties of M-Complex Symmetric Operators”. Studia Universitatis Babeș-Bolyai Mathematica 62, no. 2 (June 15, 2017): 233–248. Accessed February 5, 2025. https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/1807.