1. Ainsworth, M. D. S. (1969). Object relations, dependency, and attachment: a theoretical review of the infant-mother relationship. Child Development, 40(4), 969–1025.
2. Ainsworth, M. D. S., & Wittig, B. A. (1969). Attachment and the exploratory behaviour of one year-olds in a strange situation. In B. M. Foss (Ed.), Determinants of infant behaviour (pp. 113–136). London: Methuen.
3. Ainsworth, M. D. S. (1990). Some considerations regarding attachment theory and assessment relevant to attachments beyond infancy. In M. T. Greenberg, D. Cichetti, & E. M. Cummings (Eds.), Attachment in the preschool years (pp. 463–488). Chicago: University of Chicago Press.
4. Belsky, J., Garduque, L., & Hrncir, E. (1984). Assessing performance, competence, and executive capacity in infant play: Relations to home environment and security of attachment. Developmental Psychology, 20(3), 406–417.
5. Bowlby, J. (1982). Attachment and loss: Attachment. New York: Basic Books.