@article{1195525643,
author = {Yosida, K\^osaku},
title = {A characterization of the second order elliptic differential operators},
journal = {Proc. Japan Acad.},
volume = {31},
number = {9},
year = {1955},
pages = { 406-409},
language = {en},
url = {http://dml.mathdoc.fr/item/1195525643}
}
Yosida, Kôsaku. A characterization of the second order elliptic differential operators. Proc. Japan Acad., Tome 31 (1955) no. 9, pp. 406-409. http://gdmltest.u-ga.fr/item/1195525643/