Ainsworth, M. D. S., Blehar, M. C., Waters, E., & Wall, S. 1978 Patterns of Attachment: A psychological study of the strange situation. Hillsdale, NJ: Erlbaum.
Ainsworth, M. D. S., & Eichberg, C. G. 1991 Effects on infant-mother attachment of mother's unresolved loss of an attachment figure or other traumatic experiences. In C. M. Parkes, J. Stevenson-Hinde, & P. Marris (Eds.), Attachment across the life cycle. London: Routledge. Pp.160-183.
Bowlby, J. 1969/1982 Attachment and loss: Vol.1 Attachment. New York: Basic Books.
Bowlby, J. 1973 Attachment and loss: Vol.2. Separation. New York: Basic Books.
Bowlby, J 1980 Attachment and loss: Vol.3. Loss. New York: Basic Books.