@unpublished{SchulzeSterninShatalov2008,
  author  = {Bert-Wolfgang Schulze and Boris Sternin and Victor Shatalov},
  title   = {On the index of differential operators on manifolds with conical singularities},
  institution = {Institut f{\"u}r Mathematik},
  series    = {Preprint},
  number    = {(1997) 10},
  year    = {2008},
}