Warning - the bibtex entry below may be invalid: 
Missing 'booktitle' field 
@inproceedings{GroupExp,
  author = "Karen Petrie with Warwick Harvey and Tom Kelsey",
  journal = "In Proc. SymCon 2003",
  pages = "86-97",
  title = "Symmetry Group Expressions for CSPs",
  url = "http://4c.ucc.ie/~bms/SymCon03/papers.html",
  year = "2003",
}