@article{AUPCM_2015_14_a0,
     author = {Skrzy\'nski, Marcin},
     title = {A note on preserving the spark of a matrix},
     journal = {Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica},
     publisher = {mathdoc},
     number = {14},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUPCM_2015_14_a0/}
}