@article{JRAM_1976__280_151673,
     author = {Albert Schneider},
     title = {On spectral theory for singular {S-hermetian} difference systems.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {77--90},
     year = {1976},
     volume = {280},
     zbl = {0318.39002},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1976__280_151673/}
}