@article{NUMA_1980__35_186281,
     author = {G.A., Dougalis, V.A., Serbin, S.M. Baker},
     title = {An {Approximation} {Theorem} for {Second-Order} {Evolution} {Equations.}},
     journal = {Numerische Mathematik},
     pages = {127--142},
     publisher = {mathdoc},
     volume = {35},
     year = {1980},
     zbl = {0445.65075},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1980__35_186281/}
}