@misc{GrowitschWetzel2008,
  author    = {Christian Growitsch and Heike Wetzel},
  title     = {Testing for economies of scope in European railways: An efficiency analysis},
  institution = {Fr{\"u}here Fachbereiche},
  series    = {University of L{\"u}neburg Working paper series in economics},
  number    = {72},
  type      = {researchpaper},
  year        = {2008},
}