Lyublena Antova Christoph Koch Dan Olteanu 10<sup>10<sup>6</sup></sup> Worlds and Beyond: Efficient Representation and Processing of Incomplete Information. 606-615 2007 conf/icde/2007 ICDE http://dx.doi.org/10.1109/ICDE.2007.367906 db/conf/icde/icde2007.html#AntovaKO07