Epidemiology of Sindbis virus infections in Finland 1981–96: possible factors explaining a peculiar disease pattern - Brummer-Korvenkontio, M; Vapalahti, O; Kuusisto, P; Saikku, P; Manni, T; Koskela, P; Nygren, T; Brummer-Korvenkontio, H; Vaheri, A (Epidemiol Infect, 2002)