@conference{Schiex95a,
author = "T. Schiex and H. Fargier and G. Verfaillie",
address = "ijcai95l",
booktitle = "ijcai95p",
month = "aug",
pages = "631-637",
title = "{V}alued {C}onstraint {S}atisfaction {P}roblems: hard and easy
                   problems",
year = "1995",
}