@article{ProellerSiebartPolzer2008,
  author    = {Proeller, Isabella and Siebart, Patricia and Polzer, Tobias},
  title     = {Corporate Governance von NPOs},
  isbn      = {978-3-85499-447-3},
  year      = {2008},
  language  = {de}
}
@article{ProellerSiegel2008,
  author    = {Proeller, Isabella and Siegel, John Philipp},
  title     = {Die Rolle der Regierungszentrale in der strategischen Steuerung : internationale Perspektiven},
  isbn      = {978-3-03-823460- 9},
  year      = {2008},
  language  = {de}
}