1. A method of filtering a key-word search of a universe of documents wherein the universe comprises a plurality of regions, the method comprising the steps of: creating a first region-set identifying regions in the universe satisfying a first criterion; creating a second region-set identifying regions in the universe satisfying a second criterion; creating a third region-set from said first and said second region-set in accordance with a third criterion; and presenting as results documents from regions of said third region-set.