@article{EJDE_2003__2003__a21,
     author = {Laurence, Peter and Stredulinsky, Edward},
     title = {A comparison principle for an {American} option on several assets: index and spread options},
     journal = {Electronic Journal of Differential Equations},
     publisher = {mathdoc},
     volume = {2003},
     year = {2003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2003__2003__a21/}
}