@unpublished{GilKrainerMendoza2009,
  author  = {Juan B. Gil and Thomas Krainer and Gerardo A. Mendoza},
  title   = {On rays of minimal growth for elliptic cone operators},
  institution = {Institut f{\"u}r Mathematik},
  series    = {Preprint},
  number    = {(2006) 02},
  year    = {2009},
}