@phdthesis{buettner2005gesichertes,
  author = {B{\"{u}}ttner, Michael},
  advisor = {Niedermayer, Heiko and Dressler, Falko},
  title = {{Gesichertes Voice-over-IP mit Vovida}},
  institution = {Wilhelm-Schickard-Institute for Computer Science},
  year = {2005},
  month = {November},
  school = {University of Tuebingen},
  type = {Pre-Master's Thesis (Studienarbeit)}
}