@article{MOMA_1991__112_3_178532,
     author = {Todor Gramchev},
     title = {Semilinear {Hyperbolic} {Systems} and {Equations} with {Singular} {Initial} {Data.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {99--114},
     publisher = {mathdoc},
     volume = {112},
     number = {3},
     year = {1991},
     zbl = {0747.35020},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1991__112_3_178532/}
}