1. Institute for Information and Communications Policy: 2017 Survey on information communication media usage time and information behavior (1981)
2. Marjorie, F.V.: An Introduction to Nonverbal Communication. Shinchosha, Shinjuku (1987). Translator, Tadashi, I
3. Lo, S.-K.: The nonverbal communication functions of emoticons in computer-mediated communication. CyberPsychology & Behavior 11, 595–597 (2008)
4. Nobuyuki, H., Yusuke, U., Shuji, M.: Effects of emoticons and pictograms on communication of emotional states via mobile text-messaging. Jpn J. Res. Emot. 22(1), 20–27 (2014)
5. Hirokazu, B., Yoko, O., Kota, O., Kazu, O.: Possibility of communication by drawing and voice via Pc network in childcare. Jpn J. Educ. Media Res. 17(1), 37–47 (2010)