Ricardo A. Baeza-Yates Arjen P. de Vries Hugo Zaragoza Berkant Barla Cambazoglu Vanessa Murdock Ronny Lempel Fabrizio Silvestri Advances in Information Retrieval - 34th European Conference on IR Research, ECIR 2012, Barcelona, Spain, April 1-5, 2012. Proceedings 7224 2012 Springer Lecture Notes in Computer Science http://dx.doi.org/10.1007/978-3-642-28997-2 978-3-642-28996-5 ECIR db/conf/ecir/ecir2012.html