@presentation{petersen2008qualitative,
  author = {Petersen, Wiebke and Heinrich, Petja},
  howpublished = {presented at the 32th annual meeting of the Classification Society in Hamburg },
  interhash = {cb0721cb3aa84ba0898e3afc784559c8},
  intrahash = {cd5002cf2f214097cb7ff855b4af5db3},
  month = {07},
  title = {Qualitative Citation Analysis Based on Formal Concept Analysis},
  url = {http://user.phil-fak.uni-duesseldorf.de/~petersen/slides/Petersen_Heinrich_GFKL2008_slides.pdf},
  year = 2008
}