Sarah H. Broman & Wallace Kennedy 
Retardation in Young Children [PDF ebook] 
A Developmental Study of Cognitive Deficit

Results of the Collaborative Perinatal Project report disclose the risk factors for mental retardation found in children examined from the prenatal period to age seven. Both biological and social risk factors are analyzed for both severe and mild cognitive deficits. The authors of this volume investigated the etiologies of the neurological subgroups of the retarded and reveal, through comparisons with non-retarded groups, important population factors related to normal cognitive development.