@conference{Freuder91a,
author = "Eugene C. Freuder",
address = "aaai91l",
booktitle = "aaai91p",
keywords = "CSP, representation compacte",
pages = "227-233",
title = "{E}liminating {I}nterchangeable {V}alues in {C}onstraint
                   {S}atisfaction {P}roblems",
year = "1991",
}