@article{10_1090_S0894_0347_99_00292_1,
     author = {Liu, Tai-Ping and Yang, Tong},
     title = {\ensuremath{\mathit{L}}₁ stability for 2{\texttimes}2 systems of hyperbolic conservation laws},
     journal = {Journal of the American Mathematical Society},
     pages = {729--774},
     year = {1999},
     volume = {12},
     number = {3},
     doi = {10.1090/S0894-0347-99-00292-1},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-99-00292-1/}
}