@INPROCEEDINGS{
        NVsea12.2,
        AUTHOR = "G. Navarro and D. Valenzuela",
	TITLE = "Space-Efficient Top-k Document Retrieval",
	BOOKTITLE = "Proc. 11th International Symposium on Experimental 
		     Algorithms (SEA)",
        YEAR = "2012",
	SERIES = "LNCS 7276",
        PAGES = "307--319"
    }