@article{GDZPPN002061260,
title = {Scattering Theory for Elliptic Operators of Arbitrary Order},
journal = {Commentarii mathematici Helvetici},
volume = {49},
year = {1974},
pages = {84-113},
zbl = {0288.47012},
url = {http://dml.mathdoc.fr/item/GDZPPN002061260}
}
Schechter, Martin. Scattering Theory for Elliptic Operators of Arbitrary Order. Commentarii mathematici Helvetici, Tome 49 (1974) pp. 84-113. http://gdmltest.u-ga.fr/item/GDZPPN002061260/