@article{bw00,
author={R. Back. and J. von Wright},
title={Contracts, games and refinement},
journal={Information and Computation},
volume={156},
pages="25-45",
year={2000},
}

@article{bw95,
author={R. Back. and J. von Wright},
title={Games and winning strategies},
journal={Information Processing Letters},
volume={53},
pages={165},
year={1995},
}

@book{bw98,
author={R. Back. and J. von Wright},
title={{Refinement Calculus: A Systematic Introduction}},
publisher="Springer-Verlag",
year=1998}

@book{m94a,
author={C. Morgan},
title={{Programming from Specifications}},
publisher="Prentice Hall",
year=1994}