@article{NUMA_1971__17_132066,
     author = {B. KNAUER},
     title = {Untere {Schranken} f\"ur die {Eigenwerte} selbstadjungierter positivdefiniter {Operatoren.}},
     journal = {Numerische Mathematik},
     pages = {166--171},
     publisher = {mathdoc},
     volume = {17},
     year = {1971},
     zbl = {0206.46004},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1971__17_132066/}
}