Martin Heckmann Kazuhiro Nakadai Hirofumi Nakajima Robust Intonation Pattern Classification in Human Robot Interaction. 3137-3140 2011 INTERSPEECH conf/interspeech/2011 db/conf/interspeech/interspeech2011.html#HeckmannNN11 https://doi.org/10.21437/Interspeech.2011-785