@article{NUMA_1972__20_132176,
     author = {R.S. Varga and W.J. Kammerer},
     title = {On {Asymptotically} {Best} {Norms} for {Powers} of {Operators.}},
     journal = {Numerische Mathematik},
     pages = {93--98},
     publisher = {mathdoc},
     volume = {20},
     year = {1972},
     zbl = {0232.65038},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1972__20_132176/}
}