@ARTICLE{
author={Cvetkovic Ljiljana,Kostic Vladimir R,Bru Rafael,Pedroche Francisco},
year={2011},
title={A simple generalization of Gergorin's theorem},
journal={ADVANCES IN COMPUTATIONAL MATHEMATICS},
volume={35},
number={2-4},
pages={271-280},
document_type={Article},
} 

@ARTICLE{
author={Bru Rafael,Cvetkovic Ljiljana,Kostic Vladimir R,Pedroche Francisco},
year={2010},
title={Sums of Sigma-strictly diagonally dominant matrices},
journal={LINEAR & MULTILINEAR ALGEBRA},
volume={58},
number={1},
pages={75-78},
document_type={Article},
} 

@ARTICLE{
author={Bru Rafael,Cvetkovic Ljiljana,Kostic Vladimir R,Pedroche Francisco},
year={2010},
title={Characterization of alpha 1 and alpha 2-matrices},
journal={CENTRAL EUROPEAN JOURNAL OF MATHEMATICS},
volume={8},
number={1},
pages={32-40},
document_type={Article},
}