American Journal of Mental Retardation

Spinath, F.M. and Harlaar, N. and Ronald, Angelica and Plomin, R. (2004) Substantial genetic influence on mild mental impairment in early childhood. American Journal of Mental Retardation 109 (1), pp. 34-43. ISSN 0895-8017.

High Ability Studies

Ronald, Angelica and Spinath, F.M. and Plomin, R. (2002) The aetiology of high cognitive ability in early childhood. High Ability Studies 13 (2), pp. 103-114. ISSN 1359-8139.

Intelligence

Spinath, F.M. and Ronald, Angelica and Harlaar, N. and Price, T.S. and Plomin, R. (2003) Phenotypic g early in life: on the etiology of general cognitive ability in a large population sample of twin children aged 2–4 years. Intelligence 31 (2), pp. 195-210. ISSN 0160-2896.