@misc{MuellerBaldo2015,
  author    = {Kai-Markus M{\"u}ller and Davide Baldo},
  title     = {Method to determine willingness-to-pay},
  url       = {https://depatisnet.dpma.de/DepatisNet/depatisnet?action=bibdat\&docid=EP000003156960A1},
  year      = {2015}
}