HCI International 2021 - Late Breaking Papers: Multimodality, eXtended Reality, and Artificial Intelligence - Constantine Stephanidis, Masaaki Kurosu, Jessie Y. C. Chen, Gino Fragomeni, Norbert Streitz, Shin'ichi Konomi, Helmut Degen, Stavroula Ntoa (Springer, 2021)