@article{ETNA_2004__17__a12,
     author = {Psarrakos,  Panayiotis J.},
     title = {On the estimation of the \(q\)-numerical range of monic matrix polynomials},
     journal = {Electronic transactions on numerical analysis},
     pages = {1--10},
     year = {2004},
     volume = {17},
     zbl = {1065.15033},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ETNA_2004__17__a12/}
}