@article{20801,
      author = {Weltorganisation, Fuer Geistiges Eigentum,},
      url = {http://tind.wipo.int/record/20801},
      title = {Allgemeine Information zur Sechsten Ausgabe der  Internationalen Patentklassifikation /},
      recid = {20801},
      pages = {1 volume (various paging) ;},
}