8Tolarova MM, Cervenka J. Classification and birth prevalence of orofacial clefts [J]. Am J Med Genet, 1998, 75 (2) : 126.
9Hofstee Y, Koxs N, Hennekam RCM. Genetic survey of a group of children with clefting: implications for genetic counseling [J]. Cleft Palate Craniofac J, 1993, 30:447.