Re: 'Population mixing, socio-economic status and incidence of childhood acute lymphoblastic leukaemia in England and Wales--analysis by census ward' and 'Childhood leukaemia and population movements in France, 1990-2003'.

Re: 'Population mixing, socio-economic status and incidence of childhood acute lymphoblastic leukaemia in England and Wales--analysis by census ward' and 'Childhood leukaemia and population movements in France, 1990-2003'.