[1]
Y. D. Plotkin and A. F. Turbin, “Reversion of linear operators disturbed on the spectrum ”, Ukr. Mat. Zhurn., vol. 23, no. 2, pp. 168–176, Feb. 1971, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/8499