Mahmood Kamil Shihab. "Generalization of Fuglede-Putnam Theorem to (p, q)−Quasiposinormal Operator and (p, q)− Co-Posinormal Operator". Tikrit Journal of Pure Science 21, no. 3 (فبراير 5, 2023): 184–186. تاريخ الوصول مايو 18, 2024. https://tjps.tu.edu.iq/index.php/tjps/article/view/1014.