Information Access Evaluation. Multilinguality, Multimodality, and Visualization 4th International Conference of the CLEF Initiative, CLEF 2013, Valencia, Spain, September 23-26, 2013. Proceedings - Forner, Pamela; Müller, Henning; Paredes, Roberto; Rosso, Paolo; Stein, Benno (Springer Berlin Heidelberg : Imprint: Springer, 2013)