@article{1250181290,
author = {Cosner, Chris},
title = {A maximum principle for weakly coupled systems of second order partial differential equations with nonnegative characteristic form},
journal = {Rocky Mountain J. Math.},
volume = {11},
number = {4},
year = {1981},
pages = { 59-74},
language = {en},
url = {http://dml.mathdoc.fr/item/1250181290}
}
Cosner, Chris. A maximum principle for weakly coupled systems of second order partial differential equations with nonnegative characteristic form. Rocky Mountain J. Math., Tome 11 (1981) no. 4, pp. 59-74. http://gdmltest.u-ga.fr/item/1250181290/