@article{oai:tsukuba.repo.nii.ac.jp:00017573,
 author = {Del, Santo Daniele and Prizzi, Martino},
 issue = {1},
 journal = {Tsukuba Journal of Mathematics},
 month = {Jun},
 pages = {189--198},
 title = {A remark on well-posedness for hyperbolic equations with singular coefficients},
 volume = {27},
 year = {2003}
}