1. Ainsworth, M.D.S., Bell, S.M.V. & Slayon, D.J. (1971). Individual differences in strange situation behaviour of one year olds. In H.R. Schaffer (Ed.), The origins of human social relations (pp. 17-57). New York: Academic Press.
2. Balint, M. (1966). Primary love and psychoanalytic technique. Oxford, UK: Ernst Klett.
3. Bowlby, J. (1982). Attachment and loss: Vol. 1. Attachment (2nd ed.). New York: Basic Books.