@article{JRAM_1975__0278_0279_151656,
     author = {Heinz-Dieter Niessen},
     title = {Spektraltheorie linksdefiniter {Differenzengleichungssysteme.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {225--265},
     publisher = {mathdoc},
     volume = {0278_0279},
     year = {1975},
     zbl = {0286.47019},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1975__0278_0279_151656/}
}