The Semantic Web: Research and Applications 9th Extended Semantic Web Conference, ESWC 2012, Heraklion, Crete, Greece, May 27-31, 2012. Proceedings - Simperl, Elena; Cimiano, Philipp; Polleres, Axel; Corcho, Oscar; Presutti, Valentina (Springer Berlin Heidelberg, 2012)