@article{EJDE_2000__2000__a68,
     author = {Ko,  Youngsang},
     title = {Regularity of the interface for the porous medium equation},
     journal = {Electronic journal of differential equations},
     year = {2000},
     volume = {2000},
     zbl = {0962.35105},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2000__2000__a68/}
}