@book{RitzBenzStender2003,
  author    = {Ritz, Thomas and Benz, Axel and Stender, Michael},
  title     = {Marktstudie mobile CRM-Systeme},
  publisher = {Fraunhofer-IRB-Verl.},
  address   = {Stuttgart},
  isbn      = {3-8167-6361-8},
  pages     = {244 S. : Ill., graph. Darst.},
  year      = {2003},
  language  = {en}
}
@book{StaatHeitzer2003,
  author    = {Staat, Manfred and Heitzer, Michael},
  title     = {Numerical methods for limit and shakedown analysis. Deterministic and probabilistic problems.},
  publisher = {John von Neumann Institute for Computing (NIC)},
  address   = {J{\"u}lich},
  isbn      = {3-00-010001-6},
  pages     = {2, xiii, 282 Seiten},
  year      = {2003},
  language  = {en}
}