@article{oai:repository.dl.itc.u-tokyo.ac.jp:00039806, author = {Ushijima, Teruo}, issue = {1}, 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 = {Mar}, note = {application/pdf}, pages = {65--127}, title = {On the generation and smoothness of semi-groups of linear operators}, volume = {19}, year = {1972} }