1. Abood, E.H., Al-loz, M.A.: On some generalization of normal operators on Hilbert space. Iraqi J. Sci. 56(2C), 1786–1794 (2015)
2. Abood, E.H., Al-loz, M.A.: On some generalization of $$(n, m)$$-normal powers operators on Hilbert space. J. Progres. Res. Math. 7(3), 1063–1070 (2016)
3. Al Mohammady, S., Beinane, S.A.O., Mahmoud, S.A.O.A.: On $$(n,m)$$-$$A$$-normal and $$(n,m)$$-$$A$$-quasinormal semi-Hilbertian space operators. Mathematica Bohemica pp 18 (2021). https://doi.org/10.21136/MB.2021.0167-19
4. Alzuraiqi, S.A., Patel, A.B.: On $$n$$-normal operators. Gen. Math. Notes 1(2), 61–73 (2010)
5. Chō, M., Na$$\breve{{\rm c}}$$tovska, B.N.: Spectral properties of $$n$$-normal operators. Filomat 32(14), 5063–5069 (2018)