@article{oai:tsukuba.repo.nii.ac.jp:00017321,
 author = {Kajitani, Kunihiko and Yagdjian, Karen},
 issue = {1},
 journal = {Tsukuba Journal of Mathematics},
 month = {Jun},
 pages = {49--85},
 title = {Quasilinear hyperbolic operators with the characteristics of variable multiplicity},
 volume = {22},
 year = {1998}
}