@article{oai:repository.dl.itc.u-tokyo.ac.jp:00039356,
 author = {Uchiyama, Koichi},
 issue = {2},
 journal = {Journal of the Faculty of Science, the University of Tokyo. Sect. 1 A, Mathematics = 東京大学理学部紀要. 第1類A, 数学},
 month = {},
 note = {application/pdf},
 pages = {233--269},
 title = {$L^2$-thory of singular perturbation of hyperbolic equations I.. A priori estimates with parameter $\varepsilon$},
 volume = {39},
 year = {1992}
}