@inproceedings{/inproc/mpc/Lowe95II,
  title = "A Graphical Calculus",
  author = "Sharon Curtis and Gavin Lowe",
  year = "1995",
  booktitle = "{Mathematics of Program Construction}",
  publisher = "Lecture Notes in Computer Science",
  url = "http://www.cs.ox.ac.uk/people/gavin.lowe/Papers/graph.ps.gz",
  volume = "947",
}