@article{MZ_1971__119_171498,
     author = {Rainer W\"ust},
     title = {Generalisation of {Rellich's} {Theorem} on {Perturbation} of {(Essentially)} {Selfadjoin} {Operators.}},
     journal = {Mathematische Zeitschrift},
     pages = {276--280},
     publisher = {mathdoc},
     volume = {119},
     year = {1971},
     zbl = {0228.47010},
     url = {http://geodesic.mathdoc.fr/item/MZ_1971__119_171498/}
}