1. Becker C, Kopp S, Wachsmuth I (2007) Why emotions should be integrated into conversational agents. Wiley, London, pp 49–68
2. Becker-Asano C (2008) WASABI: affect simulation for agents with believable interactivity. Ph.D. thesis, University of Bielefeld, Bielefeld
3. Bowlby J (1969) Attachment and loss: attachment. Basic Books, New York
4. Bowlby J (1972) Attachment and loss: separation: anxiety and anger. Basic Books, New York
5. Bowlby J (1980) Attachment and loss: loss, sadness and depression. Basic Books, New York