@article{US91,
  author = "Ungar, David and Smith, Randall B.",
  title = "{SELF: The power of simplicity}",
  journal = "List and Symbolic Computation: An International Journal",
  volume = "4",
  number = "3",
  month = "Jun.",
  year = "1991",
  url = "http://www.cs.berkeley.edu/~jcondit/pl-prelim/ungar87self.ps",
}