@article{Heller2002,
  author    = {Heller, Wilfried},
  title     = {Spatial development of the economy and spatial mobility in post-socialist Romania},
  year      = {2002},
  language  = {en}
}
@article{Heller2002,
  author    = {Heller, Wilfried},
  title     = {European border cities in the process of radial change-new urban forms in the transition from national isolation to transnational networks},
  year      = {2002},
  language  = {en}
}