@article{Freuder92,
author = "E.C. Freuder and R.J. Wallace",
journal = "ai",
keywords = "CSP, satisfaction partielle, optimisation,preferences,
                   additif",
month = "dec",
pages = "21-70",
title = "{P}artial {C}onstraint {S}atisfaction",
volume = "58",
year = "1992",
}