@techreport{WangHelmreichLochner2011,
  type      = {Working Paper},
  author    = {Wang-Helmreich, Hanna and Lochner, Stefan},
  title     = {Natural gas in road transportation : a low-emission bridging technology?},
  series    = {EWI working paper},
  volume    = {14,2011},
  institution = {Inst. of Energy Economics at the Univ. of Cologne},
  address   = {Cologne},
  pages     = {35},
  year      = {2011},
  language  = {en}
}