@unpublished{HernandezMorcilloPlieningerBieling2013,
  author  = {M{\´o}nica Hern{\´a}ndez-Morcillo and Tobias Plieninger and Claudia Bieling},
  title   = {An empirical review of cultural ecosystem services indicators},
  institution = {Drittmittelprojekt {\"O}kosystemleistungen},
  year    = {2013},
}