European Journal of Epidemiology
European Journal of Epidemiology > 1998 > 14 > 2 > 125-128
European Journal of Epidemiology > 1998 > 14 > 4 > 339-342
European Journal of Epidemiology > 1998 > 14 > 2 > 125-128
European Journal of Epidemiology > 1998 > 14 > 4 > 339-342