Aetiology of acute respiratory infection in preschool children requiring hospitalisation in Europe—results from the PED-MERMAIDS multicentre case–control study oleh Cristina Calvo, Andrew Riordan, Liviana Da Dalt, Federico Martinón-Torres, Peter Horby, Julia A Bielicki, Maria Tsolia, Michael Sharland, Herman Goossens, Marion Koopmans, Despoina Gkentzi, Peter J Openshaw, Menno D de Jong, Elias Iosifidis, Emmanuel Roilides, Carlo Giaquinto, Louise Sigfrid, Margareta Ieven, Malte Kohns Vasconcelos, Pablo Rojo, Cristina Epalza, Sigita Burokiene, Hanna Renk, Samsul Islam, Vana Spoulou, Katherine Loens, Daniele Donà, Veerle Matheeussen, Savvas Papachristou, Manuel Gijon, Chiara Minotti, Jessica Jarvis, Aggeliki Syggelou, Maggie Nyirenda Nyang’wa, Sophie Keers, Anna-Lena Gemmel, Carmen D’Amore, Marta Ciofi degli Atti, Carmen Rodríguez-Tenreiro Sánchez, Tessa Goetghebuer, Markus Hufnagel, Pieter L A Fraaij