@article{10_4064_sm_45_3_257_271,
     author = {E. M\"uller-Pfeiffer},
     title = {\"Uber die {Halbbeschr\"anktheit} und das {Spektrum} des {Operators} $(-\ensuremath{\Delta})^{m}+q(x)$},
     journal = {Studia Mathematica},
     pages = {257--271},
     publisher = {mathdoc},
     volume = {45},
     number = {3},
     year = {1973},
     doi = {10.4064/sm-45-3-257-271},
     language = {de},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-45-3-257-271/}
}