@misc{SiebertHoogeveenFrenken2006,
  author    = {Stefan Siebert and Jippe Hoogeveen and Karen Frenken},
  title     = {Irrigation in Africa, Europe and Latin America : update of the Digital Global Map of Irrigation Areas to version 4},
  booktitle = {Frankfurt hydrology paper ; 5},
  institution = {Geowissenschaften},
  series    = {Frankfurt Hydrology Paper},
  number    = {5},
  type      = {workingpaper},
  year        = {2006},
}