@article{NUMA_1971__17_132058,
     author = {A.N. jr. WILLSON},
     title = {A {Useful} {Generalization} of the {P0} {Matrix} {Concept,.}},
     journal = {Numerische Mathematik},
     pages = {62--70},
     publisher = {mathdoc},
     volume = {17},
     year = {1971},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1971__17_132058/}
}