Nasli Bakir, Aissa, and Salah Mecheri. “N-Multiplicity and Spectral Properties for (M,k)-Quasi-*-Class Q Operators”. Eurasian Mathematical Journal 14, no. 2 (June 30, 2023): 79–93. Accessed September 15, 2025. https://emj.enu.kz/index.php/main/article/view/286.