Diego Ceccarelli Claudio Lucchese Salvatore Orlando Raffaele Perego Fabrizio Silvestri Caching query-biased snippets for efficient retrieval. 93-104 2011 EDBT http://doi.acm.org/10.1145/1951365.1951379 conf/edbt/2011 db/conf/edbt/edbt2011.html#CeccarelliLOPS11