Hatamleh, R. and Zolotarev, V.A. (2016) “Triangular models of commutative systems of linear operators close to unitary operators”,
Ukrains’kyi Matematychnyi Zhurnal, 68(5), pp. 694–711. Available at:
https://umj.imath.kiev.ua/index.php/umj/article/view/1872 (Accessed: 26 April 2025).