Ricardo A. Baeza-Yates Massimiliano Ciaramita Peter Mika Hugo Zaragoza Towards Semantic Search. 4-11 2008 NLDB http://dx.doi.org/10.1007/978-3-540-69858-6_2 conf/nldb/2008 db/conf/nldb/nldb2008.html#Baeza-YatesCMZ08