@article{MZ_1988__197_1_183718,
     author = {R.R.del Rio Castillo},
     title = {Ein {Gegenbeispiel} zur {Stabilit\"at} des absolut stetigen {Spektrums} gew\"ohnlicher {Differentialoperatoren.}},
     journal = {Mathematische Zeitschrift},
     pages = {61--68},
     publisher = {mathdoc},
     volume = {197},
     number = {1},
     year = {1988},
     zbl = {0618.34022},
     url = {http://geodesic.mathdoc.fr/item/MZ_1988__197_1_183718/}
}