Cancer morbidity in British military veterans included in chemical warfare agent experiments at Porton Down: cohort study. - Carpenter, L; Linsell, L; Brooks, C; Keegan, T; Langdon, T; Doyle, P; Maconochie, N; Fletcher, T; Nieuwenhuijsen, M; Beral, V; Venables, K (BMJ (Clinical research ed.), 2009)