@article{
    mrjcss2,
    author = {Mannila, Heikki and R{\"a}ih{\"a}, K.-J.},
    title = "Design by example: an application of {A}rmstrong relations",
    journal = "Journal of Computer and System Sciences",
    number = "2",
    volume = "33",
    year = "1986",
    pages = "126-141"
}