@article{ETNA_2004__18__a3,
     author = {Calvetti, D. and Lewis, B. and Reichel, L. and Sgallari, F.},
     title = {Tikhonov regularization with nonnegativity constraint},
     journal = {Electronic transactions on numerical analysis},
     pages = {153--173},
     publisher = {mathdoc},
     volume = {18},
     year = {2004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ETNA_2004__18__a3/}
}