@unpublished{CoriascoSchroheSeiler2008,
  author  = {Sandro Coriasco and Elmar Schrohe and J{\"o}rg Seiler},
  title   = {Bounded imaginary powers of differential operators on manifolds with conical singularities},
  institution = {Institut f{\"u}r Mathematik},
  series    = {Preprint},
  number    = {(2001) 12},
  year    = {2008},
}