@article{oai:tsukuba.repo.nii.ac.jp:00017223,
 author = {Morioka, Tatsushi},
 issue = {2},
 journal = {Tsukuba Journal of Mathematics},
 month = {Oct},
 pages = {537--550},
 title = {Une perturbation des operateurs microhypoelliptiques},
 volume = {22},
 year = {1998}
}