@article{Hoare74a,
  title = "Consistent and Complementary Formal Theories of the Semantics of Programming Languages",
  author = "C.A.R. Hoare and P.E. Lauer",
  year = "1974",
  journal = "Acta Informatica",
  number = "2",
  pages = "135--153",
  volume = "3",
}