@article{10_1007_s10587_015_0158_5,
     author = {Chen, Yizhi and Zhao, Xianzhong and Liu, Zhongzhu},
     title = {On upper triangular nonnegative matrices},
     journal = {Czechoslovak Mathematical Journal},
     pages = {1--20},
     publisher = {mathdoc},
     volume = {65},
     number = {1},
     year = {2015},
     doi = {10.1007/s10587-015-0158-5},
     mrnumber = {3336023},
     zbl = {06433719},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1007/s10587-015-0158-5/}
}