@article{COCV_2007__13_4_776_0,
     author = {Guo, Bao-Zhu and Zhang, Zhi-Xiong},
     title = {On the well-posedness and regularity of the wave equation with variable coefficients},
     journal = {ESAIM: Control, Optimisation and Calculus of Variations},
     pages = {776--792},
     publisher = {EDP-Sciences},
     volume = {13},
     number = {4},
     year = {2007},
     doi = {10.1051/cocv:2007040},
     mrnumber = {2351403},
     language = {en},
     url = {http://www.numdam.org/articles/10.1051/cocv:2007040/}
}