A structural MRI study in monozygotic twins concordant or discordant for attention/hyperactivity problems: Evidence for genetic and environmental heterogeneity in the developing brain. - Dennis van 't Ent; Hanne Lehn; Eske M. Derks; James J. Hudziak; Niels M. Van Strien; Dick J. Veltman; Eco J. C. de Geus; Richard D. Todd; Dorret I. Boomsma (NeuroImage, 2007)