@techreport{ATheory,
  title = "A theory of communicating sequential processes",
  author = "A. W. Roscoe and S.D. Brookes and C. A. R. Hoare",
  year = "1981",
  institution = "Oxford University Computing Laboratory",
  month = "May",
  number = "{PRG-16}",
  url = "http://www.cs.ox.ac.uk/people/bill.roscoe/publications/1.pdf",
}