@article{ETNA_2007__27__a0,
     author = {Robnik, Marko and Romanovski, Valery G.},
     title = {The difference equation related to the problem of the hydrogen atom in a strong magnetic field},
     journal = {Electronic transactions on numerical analysis},
     pages = {163--176},
     publisher = {mathdoc},
     volume = {27},
     year = {2007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ETNA_2007__27__a0/}
}