1. Ainsworth, M. D. (1985). Attachments across the life span. Bulletin of the New York Academy of Medicine, 61, 792.
2. Ainsworth, M. D., Blehar, M. C., Waters, E., & Walls, S. (1978). Patterns of attachment: A psychological study of the strange situation. Hillsdale, NJ: Lawrence Erlbaum Associates; distributed by Halsted Press Division of Wiley.
3. Barlow, J., & Parsons, J. (2005). Group-based parent-training programmes for improving emotional and behavioural adjustment in 0–3 year old children. Campbell Systematic Reviews.
4. Barlow, J., Smailagic, N., Bennett, C., Huband, N., Jones, H., & Coren, E. (2011). Individual and group based parenting programmes for improving psychosocial outcomes for teenage parents and their children (Review). Cochrane Database of Systematic Reviews.
5. Bhaskar, R. (1975). A realist theory of science. Leeds: Leeds Books Ltd.