@Inproceedings{ls_leimeister,
  author = {Hoffmann, A. and Hoffmann, H. and Leimeister, J. M.},
  title  = {Nutzerintegration in die Anforderungserhebung für Ubiquitous Computing Systeme},

  year   = {2010},
  number = {27},
  url    = {http://www.uni-kassel.de/fb7/ibwl/leimeister/pub/JML_188.pdf},

  const  = {\ text}
}
@Inproceedings{ls_leimeister,
  author = {Hoffmann, A. and Hoffmann, H. and Leimeister, J. M.},
  title  = {Nutzerintegration in die Anforderungserhebung für Ubiquitous Computing Systeme},

  year   = {2010},
  number = {27},
  url    = {http://pubs.wi-kassel.de/wp-content/uploads/2013/03/JML_232.pdf},

  const  = {\ text}
}