@UNPUBLISHED{publication1, title = "Sharp regularity for the inhomogeneous porous medium equation", author = "{ARA{\'{U}}JO, Dami{\~{a}}o J.} and {MAIA, Anderson F.} and {URBANO, Jos{\'{e}} Miguel}", year = "2017-06-14", url = "http://www.mat.uc.pt/preprints/eng\_2017.html", note = "" }