@article{MS2_1960__8_165742,
     author = {Arne Persson},
     title = {Bounds for the {Discrete} {Part} of the {Spectrum} of a {Semi-Bounded} {Schr\"odinger} {Operator.}},
     journal = {Mathematica Scandinavica},
     pages = {143--153},
     publisher = {mathdoc},
     volume = {8},
     year = {1960},
     zbl = {0145.14901},
     url = {http://geodesic.mathdoc.fr/item/MS2_1960__8_165742/}
}