@article{EJDE_2000__2000__a176,
     author = {Lieberman,  Gary M.},
     title = {The maximum principle for equations with composite coefficients},
     journal = {Electronic journal of differential equations},
     year = {2000},
     volume = {2000},
     zbl = {0952.35025},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2000__2000__a176/}
}