@ARTICLE{
author={Hai Guojun,Cvetkovic-Ilic Dragana S},
year={2017},
title={Generalized Left and Right Weyl Spectra of Upper Triangular Operator Matrices},
journal={ELECTRONIC JOURNAL OF LINEAR ALGEBRA},
volume={32},
number={},
pages={41-50},
document_type={Article},
} 

@ARTICLE{
author={Cvetkovic-Ilic Dragana S,Hai Guojun,Chen Alatancang},
year={2015},
title={Some results on Fredholmness and boundedness below of an upper triangular operator matrix},
journal={JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS},
volume={425},
number={2},
pages={1071-1082},
document_type={Article},
}