@article{Weigand1991,
  author    = {Weigand, Christoph},
  title     = {A Solution to the Scheduling Problem Taking into Account Quality},
  series = {Operations research '91 : extended abstracts of the 16th Symposium on Operations Research held at the University of Trier at September 9 - 11, 1991 / [GM{\"O}OR]. Peter Gritzmann ... (eds.)},
  journal   = {Operations research '91 : extended abstracts of the 16th Symposium on Operations Research held at the University of Trier at September 9 - 11, 1991 / [GM{\"O}OR]. Peter Gritzmann ... (eds.)},
  publisher = {Physica-Verl.},
  address   = {Heidelberg},
  isbn      = {3790806080},
  pages     = {373 -- 375},
  year      = {1991},
  language  = {en}
}
@article{JacobsQuernheimAghadavoodiJolfaei1991,
  author    = {Jacobs, Stephan and Quernheim, Ulrich and Aghadavoodi Jolfaei, Masoud},
  title     = {Performance Evalutation of three Access Protocols for VSAT Networks / Ulrich Quernheim, Stephan Jacobs, Masoud Aghadavoodi Jolfaei},
  series = {Proceedings of the second European Conference on Satellite Communications : ECSC-2 ; Palais de Congr{\`e}s, Li{\`e}ge, Belgium, 22 - 24 October 1991 / [ed.: Brigitte Kaldeich]},
  journal   = {Proceedings of the second European Conference on Satellite Communications : ECSC-2 ; Palais de Congr{\`e}s, Li{\`e}ge, Belgium, 22 - 24 October 1991 / [ed.: Brigitte Kaldeich]},
  publisher = {ESA Publ. Div.},
  address   = {Noordwijk},
  isbn      = {92-9092-170-6},
  pages     = {XXXII, 533 S. : Ill., graph. Darst.},
  year      = {1991},
  language  = {en}
}
@article{Mackenstein1991,
  author    = {Mackenstein, Hans},
  title     = {The role of Germany, Japan and the United States on the ECU-bond markets / Hans Wilhelm Mackenstein},
  series = {De pecunia. 3 (1991), H. 1},
  journal   = {De pecunia. 3 (1991), H. 1},
  isbn      = {1015-6283},
  pages     = {113 -- 150},
  year      = {1991},
  language  = {en}
}