@article{oai:tsukuba.repo.nii.ac.jp:00016174,
 author = {Koike, Minoru},
 issue = {1},
 journal = {Tsukuba Journal of Mathematics},
 month = {Jun},
 pages = {55--67},
 title = {On the microlocal hypoellipticity of pseudodifferential operators},
 volume = {8},
 year = {1984}
}