@inproceedings{AFRV93,

    Author = "M. Alpuente and M. Falaschi and M.J. Ramis and G. Vidal",

    Title = "{N}arrowing {A}pproximations as an {O}ptimization for
             {E}quational {L}ogic {P}rograms",

    Booktitle = "Proc. of Fifth Int'l Symp. on Programming Language
                 Implementation and Logic Programming, PLILP'93, Tallinn,
                 Estonia",

    Editor = "M. Bruynooghe and J. Penjam",

    Series = "Lecture Notes in Computer Science",

    Volume = "714",

    Pages = "391-409",

    Publisher = "Springer-Verlag, Berlin",

    Year = "1993"

}