%% -*-BibTeX-*- @Article{KoHoKo98, author = "A. M. C. A. Koster and C. P. M. {v}an Hoesel and A. W. J. Kolen", title = "The Partial Constraint Satisfaction Problem: Facets and Lifting Theorems", journal = "Operations Research Letters", volume = "23", number = "3--5", pages = "89--97", year = "1998", language = "English", }