@unpublished{Baer2012,
  author  = {Christian B{\"a}r},
  title   = {Some properties of solutions to weakly hypoelliptic equations},
  institution = {Institut f{\"u}r Mathematik},
  series    = {Preprints des Instituts f{\"u}r Mathematik der Universit{\"a}t Potsdam},
  number    = {1(2012)22},
  year    = {2012},
}