@article{10_4064_ap78_1_5,
     author = {Mokhtar Kirane and Salim Messaoudi},
     title = {Nonexistence results for the {Cauchy} problem
 of some systems of hyperbolic equations},
     journal = {Annales Polonici Mathematici},
     pages = {39--47},
     publisher = {mathdoc},
     volume = {78},
     number = {1},
     year = {2002},
     doi = {10.4064/ap78-1-5},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap78-1-5/}
}