@article{MZ_1977__155_172560,
     author = {Heinz-Willi Goelden},
     title = {On {Non-Degeneracy} of the {Ground} {State} of {Schr\"odinger} {Operators.}},
     journal = {Mathematische Zeitschrift},
     pages = {239--248},
     publisher = {mathdoc},
     volume = {155},
     year = {1977},
     zbl = {0353.35032},
     url = {http://geodesic.mathdoc.fr/item/MZ_1977__155_172560/}
}