@article{MZ_1973__135_172014,
     author = {Agnes Gr\"utter},
     title = {Wesentliche {Selbstadjungiertheit} eines {Schr\"odinger-Operators.}},
     journal = {Mathematische Zeitschrift},
     pages = {289--292},
     publisher = {mathdoc},
     volume = {135},
     year = {1973},
     zbl = {0263.47006},
     url = {http://geodesic.mathdoc.fr/item/MZ_1973__135_172014/}
}