@techreport{MNU:parallel,
  title = "Improving {Angel}'s Parallel Operator: {Gumtree}'s Approach",
  author = "Andrew Martin and Ray Nickson and Mark Utting",
  year = "1997",
  address = "The University of Queensland, QLD 4072, Australia",
  institution = "Software Verification Research Centre",
  number = "97-15",
}