Asthma in adults and its association with chronic rhinosinusitis: the GA2LEN survey in Europe - Jarvis, D; Newson, R; Lotvall, J; Hastan, D; Tomassen, P; Keil, T; Gjomarkaj, M; Forsberg, B; Gunnbjornsdottir, M; Minov, J; Brozek, G; Dahlen, S E; Toskala, E; Kowalski, M L; Olze, H; Howarth, P; Kramer, U; Baelum, J; Loureiro, C; Kasper, L; Bousquet, P J; Bousquet, J; Bachert, C; Fokkens, W; Burney, P (Allergy, 2012)