@unpublished{MaSchulze2009,
  author  = {L. Ma and Bert-Wolfgang Schulze},
  title   = {Operators on manifolds with conical singularities},
  institution = {Institut f{\"u}r Mathematik},
  series    = {Preprint},
  number    = {(2009) 07},
  year    = {2009},
}