@book{OPUS4-3118,
  title     = {Proceedings of the 2. Ph.D. retreat of the HPI Research School on Service-oriented Systems Engineering},
  editor    = {Christoph Meinel and Andreas Polze and Mathias Weske and J{\"u}rgen Roland Friedrich D{\"o}llner and Robert Hirschfeld and Felix Naumann and Holger Giese and Hasso Plattner},
  isbn      = {978-3-940793-42-3},
  year      = {2009},
}