@Article{Kahl-1998a,
  author = 	 {Wolfram Kahl},
  title = 	 {Relational Treatment of Term Graphs With Bound Variables},
  journal = 	 {Journal of the IGPL},
  year = 	 {1998},
  volume = 	 {6},
  number = 	 {2},
  month = 	 MAR,
  pages = 	 {259--303},
  URL = 	 {http://www.oup.co.uk/igpl/Volume_06/Issue_02/#Kahl},
  abstract = {We show how and why it makes sense
              to use a relational formalisation
              instead of the usual functional one
              in the treatment of term graphs.
              Special attention is paid to term graphs with bound variables,
              that have, to our knowledge,
              never been formalised with such a generality before.

              Besides the novel treatment of term graphs themselves,
              we present an innovative relational homomorphism concept
              that for the first time allows to consider terms,
              resp.\null{} term trees
              as a special case of term graphs
              and still have the full power
              of (second-order) substitution available.}
}