References
Berry Brazelton, T. and Cramer, B. G. (1991) The Earliest Relationship, London: Karnac Books
Meggitt, C. and Sunderland, G. (2000) Child Development: An illustrated guide, London: Heinemann Child Care, pp. 7, 10, 11
Oates, J. (ed.) (1994) The Foundations of Child Development, Oxford: Blackwell in association with The Open University