中国科学院数学与系统科学研究院期刊网
Self-adjoint Perturbations of Left (right) Essential Spectrum for Upper Triangular Operator Matrices
Xiu Feng WU, Jun Jie HUANG, Alatancang
Acta Mathematica Sinica, Chinese Series . 2022, (3): 423 -434 .  DOI: 10.12386/A2022sxxb0034