Demetriou, A. (1998). Cognitive development. In A. Demetriou, W. Doise, K. F. M. van Lieshout (Eds.), Life-span developmental psychology, pp. 179-269. London: Wiley.
Hayslip Jr., Bert; Neumann, Craig S.; Louden, Linda; Chapman, Benjamin (2006). "Developmental Stage Theories". In Hersen, Michel; Thomas, Jay C. (eds.). Comprehensive Handbook of Personality and Psychopathology, Vol. 1. Personality and Everyday Functioning. Hoboken, NJ: John Wiley & Sons. pp. 115–141. ISBN9780471488385. OCLC59279973.
Carter, Linda; Grivas, John (2004). Psychology for South Australia: Stage 1. Milton, Qld.: Jacaranda. ISBN9780731400942. OCLC224074696.