@article{oai:tsukuba.repo.nii.ac.jp:00017173,
 author = {Hoshiro, Toshihiko},
 issue = {1},
 journal = {Tsukuba Journal of Mathematics},
 month = {Jun},
 pages = {131--149},
 title = {On the estimates for Helmholz operator},
 volume = {23},
 year = {1999}
}