„Prevalence and Incidence of Edwards Syndrome“. Diseases Center-Edwards Syndrome. Adviware Pty Ltd. (2008-yil 4-fevral). — „mean maternal age for this disorder is 32½“. 2004-yil 25-iyunda asl nusxadan arxivlangan. Qaraldi: 2008-yil 17-fevral.
„Prevalence and Incidence of Edwards Syndrome“. Diseases Center-Edwards Syndrome. Adviware Pty Ltd. (2008-yil 4-fevral). — „mean maternal age for this disorder is 32½“. 2004-yil 25-iyunda asl nusxadan arxivlangan. Qaraldi: 2008-yil 17-fevral.