Pedro F. Campos, T. C. Nicholas Graham, Joaquim A. Jorge, Nuno Jardim Nunes, Philippe A. Palanque, Marco Winckler: Human-Computer Interaction - INTERACT 2011 - 13th IFIP TC 13 International Conference, Lisbon, Portugal, September 5-9, 2011, Proceedings, Part I. Lecture Notes in Computer Science 6946, Springer 2011, ISBN 978-3-642-23773-7