@unpublished{NazaikinskiiSavinSchulzeetal.2008,
  author  = {Vladimir E. Nazaikinskii and Anton Savin and Bert-Wolfgang Schulze and Boris Sternin},
  title   = {On the homotopy classification of elliptic operators on manifolds with edges},
  institution = {Institut f{\"u}r Mathematik},
  series    = {Preprint},
  number    = {(2004) 16},
  year    = {2008},
}