Genetic and environmental etiologies of reading difficulties: DeFries-Fulker analysis of reading performance data from twin pairs and their nontwin siblings.
Astrom RL, Wadsworth SJ, Olson RK, Willcutt EG, Defries JC. Genetic and environmental etiologies of reading difficulties: DeFries-Fulker analysis of reading performance data from twin pairs and their nontwin siblings. Learn Individ Differ. 2012 Jun 01; 22(3):365-369.