@article{13398,
      recid = {13398},
      author = {Graham, Stuart J. H., and Hall, Bronwyn H. and Harhoff,  Dietma. and Mowery, David C.},
      title = {Post-issue patent 'quality control' : a comparative study  of US patent re-examinations and european patent  oppositions /},
      pages = {44 pages ;},
      note = {National Bureau of Economic Research (NBER) Working Paper  8807, February 2002.},
      url = {http://tind.wipo.int/record/13398},
}