@article{oai:tsukuba.repo.nii.ac.jp:00017149,
 author = {D'Ancona, Piero and Di, Flaviano Mariagrazia},
 issue = {3},
 journal = {Tsukuba Journal of Mathematics},
 month = {Dec},
 pages = {559--574},
 title = {On quasilinear hyperbolic equations with degenerate principal part},
 volume = {22},
 year = {1998}
}