Maternal age-specific rates of 47, + 21 and other cytogenetic abnormalities diagnosed in the first trimester of pregnancy in chorionic villus biopsy specimens: comparison with rates expected from observations at amniocentesis
B. Hook, Ernest et al., Maternal age-specific rates of 47, + 21 and other cytogenetic abnormalities diagnosed in the first trimester of pregnancy in chorionic villus biopsy specimens: comparison with rates expected from observations at amniocentesis, American journal of human genetics , 42(6), 1988, pp. 797-807