@article{NUMA_1974__23_132296,
     author = {E. Gekeler},
     title = {On the {Convergence} of the von {Neumann} {Difference} {Approximation} to {Hyperbolic} {Initial} {Boundary} {Value} {Problems.}},
     journal = {Numerische Mathematik},
     pages = {167--174},
     publisher = {mathdoc},
     volume = {23},
     year = {1974},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1974__23_132296/}
}