@article{1195516106,
author = {Tsutsumi, Akira and Haruki, Shigeru},
title = {Functional equations and hypoellipticity},
journal = {Proc. Japan Acad. Ser. A Math. Sci.},
volume = {58},
number = {5},
year = {1982},
pages = { 105-108},
language = {en},
url = {http://dml.mathdoc.fr/item/1195516106}
}
Tsutsumi, Akira; Haruki, Shigeru. Functional equations and hypoellipticity. Proc. Japan Acad. Ser. A Math. Sci., Tome 58 (1982) no. 5, pp. 105-108. http://gdmltest.u-ga.fr/item/1195516106/