@unpublished{KrainerSchulze2008,
  author  = {Thomas Krainer and Bert-Wolfgang Schulze},
  title   = {The conormal symbolic structure of corner boundary value problems},
  institution = {Institut f{\"u}r Mathematik},
  series    = {Preprint},
  number    = {(2004) 01},
  year    = {2008},
}