@article{oai:repository.dl.itc.u-tokyo.ac.jp:00039478, author = {Matsuzawa, Tadato}, issue = {3}, 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 = {779--790}, title = {Hypoellipticity in ultradistribution spaces}, volume = {34}, year = {1987} }