Loane M, Dolk H, Garne E, Greenlees R; EUROCAT Working Group: Haeusler M , Nelen V , Verellen-Dumoulin C , Barisic je , Randrianaivo H , Khoshnood B , Doray B , Queisser-Luft A , Rissmann A , M O'Mahony ,McDonnell B , C Mullaney , Calzolari E , E-Romagne , Bianchi F , Gatt M , M Bakker , Melve KK , Latos-Bielenska A , Dias CM , Salvador J , L Arriola , Addor MC , Wertelecki W , E Draper , Rankin J , P Boyd , Tucker D , D Wellesley . Paper 3: EUROCAT data quality indicators for population-based registries of congenital anomalies. Birth Defects Res A Clin Mol Teratol. 2011 Mar; 91 Suppl 1