J. Freitas et al.,  "Enhancing multimodal silent speech interfaces with feature selection", in 15th Annu. Conf. of the Int. Speech Communication Association (INTERSPEECH 2014), Proc., Chng E.S.,Li H.,Meng H.,Ma B.,Xie L., Ed., Singapure, Speech and Communication Association , 2014, pp. 1169-1173