@book{ChwallekFelden2006,
  author    = {Chwallek, Constanze and Felden, Birgit},
  title     = {RatingCheck : Wertsch{\"o}pfungskette / Chwallek, Constanze ; Felden, Birgit},
  publisher = {Deutscher Sparkassen Verlag},
  address   = {Stuttgart},
  year      = {2006},
  language  = {en}
}
@book{JanzGoedhuysMohnen2006,
  author    = {Janz, Norbert and Goedhuys, Micheline and Mohnen, Pierre},
  title     = {What drives productivity in Tanzanian manufacturing firms: technology or institutions? / Goedhuys, Micheline ; Janz, Norbert ; Mohnen, Pierre},
  publisher = {UnU-MERIT},
  address   = {Maastricht},
  pages     = {22 S.},
  year      = {2006},
  language  = {en}
}