@article{MZ_1972__127_171770,
     author = {Rudolf A. Hirschfeld},
     title = {On {Polynomials} in {Several} {Hilbert} {Space} {Operators.}},
     journal = {Mathematische Zeitschrift},
     pages = {224--234},
     publisher = {mathdoc},
     volume = {127},
     year = {1972},
     zbl = {0256.47004},
     url = {http://geodesic.mathdoc.fr/item/MZ_1972__127_171770/}
}