1. Trevarthen C (2001) Intrinsic motives for companionship in understanding: Their origin, development, and significance for infant mental health. Infant Ment Health J 22:95–131
2. Trevarthen C (2016) Sharing joyful friendship and imagination for meaning with infants, and their application in early intervention. In: Acquarone S (ed) Surviving the early years: the importance of early intervention with babies at risk. Karnak, London, pp 19–55
3. Trevarthen C (2017) The affectionate intersubjective intelligence of the infant, and its innate motives for relational mental health. Int J Cognit Anal Therap Relat Mental Health 1(1):11–53
4. Nagy E (2011) The newborn infant: a missing stage in developmental psychology. Infant Child Dev 20:3–19
5. Freud S (1923) Das Ich und das Es (The Ego and the Id). Internationaler Psycho-Analytischer Verlag/W.W. Norton & Company, Vienna/New York