@article{NUMA_1975__24_132348,
     author = {W. Busch and R. Esser and W. Hackbusch and U. Herrmann},
     title = {Extrapolation {Applied} to the {Method} of {Characteristics} for a first {Order} {System} of {Two} {Partial} {Differential} {Equations.} {Part} {One} : {The} {Initial} {Value} {Problem.}},
     journal = {Numerische Mathematik},
     pages = {331--354},
     publisher = {mathdoc},
     volume = {24},
     year = {1975},
     zbl = {0317.65030},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1975__24_132348/}
}