@article{02033594,
title = {A comparison principle for an American option on several assets: index and spread options.},
journal = {Electronic Journal of Differential Equations (EJDE) [electronic only]},
volume = {2003},
year = {2003},
zbl = {1036.35113},
language = {en},
url = {http://dml.mathdoc.fr/item/02033594}
}
Laurence, Peter; Stredulinsky, Edward. A comparison principle for an American option on several assets: index and spread options.. Electronic Journal of Differential Equations (EJDE) [electronic only], Tome 2003 (2003) . http://gdmltest.u-ga.fr/item/02033594/