@unpublished{NazaikinskiiSavinSchulzeetal.2008,
  author  = {Vladimir Nazaikinskii and Anton Savin and Bert-Wolfgang Schulze and Boris Sternin},
  title   = {Elliptic theory on manifolds with nonisolated singularities : III. The spectral flow of families of conormal symbols},
  institution = {Institut f{\"u}r Mathematik},
  series    = {Preprint},
  number    = {(2002) 20},
  year    = {2008},
}