The proceedings of eNTERFACE'09 can be downloaded here

You may reference them as follows:

A. Camurri, M. Mancini, G. Volpe (Eds.), 2010. Proceedings of the 5th International Summer Workshop on Multimodal Interfaces (eNTERFACE'09), DIST-University of Genova, Genova, Italy. ISBN: 13-978-88-901344-7-0