@incollection{HammerlPucherMenseetal.2009,
  author    = {Barbara Hammerl and Robert Pucher and Alexander Mense and Harald Wahl and Fritz Schm{\"o}llebeck},
  title     = {Intrinsic Motivation and Education for Sustainability},
  booktitle = {Intrinsic Motivation - An Essential Key to Success},
  year      = {2009},
}