@Article{ls_leimeister,
  author = {Dünnebeil, S. and Sunyaev, A. and Leimeister, J. M. and Krcmar, H.},
  title  = {Modular Architecture of Value-Added Applications for German Healthcare Telematics},
  journal = {Business & Information Systems Engineering},
  year   = {2012},
  number = {},
  url    = {http://pubs.wi-kassel.de/wp-content/uploads/2013/01/JML_388.pdf},

  const  = {\ text}
}
@Book{Gregory.2009,
  author = {Gregory, Jason},
  title  = {Game engine architecture},

  year   = {2009},
  number = {},
  url    = {},

  const  = {\ text}
}
@Book{Rollings.2003,
  author = {Rollings, A. and Morris, D.},
  title  = {Game Architecture and Design: A New Edition [Taschenbuch] },

  year   = {2003},
  number = {},
  url    = {},

  const  = {\ text}
}