@article{SMJ2_2001_27_1_a1,
     author = {Boiti, Chiara and Manfrin, Renato},
     title = {Formation of {Singularities} for {Weakly} {Non-Linear} {N{\texttimes}N} {Hyperbolic} {Systems}},
     journal = {Serdica Mathematical Journal},
     pages = {67--90},
     publisher = {mathdoc},
     volume = {27},
     number = {1},
     year = {2001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SMJ2_2001_27_1_a1/}
}