中国科学院数学与系统科学研究院期刊网
AMS
Semi–Fredholm Spectrum and Weyl's Theorem for Operator Matrices
Xiao Hong Cao, Mao Zheng Guo, Bin Meng,
Acta Mathematica Sinica . 2006, (1): 169 -178 .  DOI: 10.1007/s10114-004-0505-1