@unpublished{,
  author = "Bruno C. d. S. Oliveira and Martin Sulzmann",
  month = "April",
  note = "Submitted to ICFP 2008",
  title = "Objects to Unify Type Classes and GADTs",
  url = "http://www.comlab.ox.ac.uk/people/Bruno.Oliveira/objects.pdf",
  year = "2008",
}