@unpublished{HieberSchrohe2008,
  author  = {Matthias Hieber and Elmar Schrohe},
  title   = {Lρ spectral independence of elliptic operators via commutator estimates},
  institution = {Institut f{\"u}r Mathematik},
  series    = {Preprint},
  number    = {(1997) 17},
  year    = {2008},
}