EUROlinkCAT protocol for a European population-based data linkage study investigating the survival, morbidity and education of children with congenital anomalies by Nathalie Lelong, Babak Khoshnood, David Tucker, Mika Gissler, Maria Loane, Ingeborg Barisic, Miriam Gatt, Kari Klungsoyr, Amanda Neville, Anna Pierini, Anke Rissmann, Oscar Zurriaga, Joan K Morris, Paula Braz, Vera Nelen, Judith Rankin, Ester Garne, Sue Jordan, Anna Heino, Silvia Baldacci, Michele Santoro, Alessio Coi, Lorena Mezzasalma, Daniel Thayer, Svetlana V Glinianaia, Hermien de Walle, Guy Thys, Anna Latos-Bielenska, Aurora Puccini, Elisa Ballardini, Wladimir Wertelecki, Carlos Matias Dias, Gianni Astolfi, James Densem, Joachim Tan, Joanne Emma Given, Hugh Claridge, Abigail Reid, Liz Limb, Gillian Briggs, Nicholas Connor, Stine Kjaer Urhoj, Mads Damkjær, Christina Neergaard Pedersen, Annarita Armaroli, Ljubica Boban, L Renée Lutke, Nicole H A Siemensma-Mühlenberg, Nathalie Bertille, Makan Rahshenas, Clara Cavero Carbonell, Laia Barrachina Bonet, Laura García Villodre, Anna Jamry-Dziurla, Sonja Kiuru-Kuhlefelt, Lyubov Yevtushok, Nataliia Zymak-Zakutnia, Diana Akhmedzhanova, Lyubov Ostapchuk, Oksana Tsizh, Serhii Lapchenko, Ausenda Machado, Ana João Santos, Liliana Antunes, Hanitra Randrianaivo-Ranjatoelina, Elly Den Hond, Olatz Mokoroa Carollo, Ieuan Scanlon