Farrington, CP; Firth, MJ; Moulton, LH; Ravn, H; Andersen, PK; Evans, S; on behalf of the Working Group on Non-specific Effects of Vaccin; (2009) Epidemiological studies of the non-specific effects of vaccines: II - methodological issues in the design and analysis of cohort studies. Tropical medicine & international health, 14 (9). pp. 977-985. ISSN 1360-2276 DOI: https://doi.org/10.1111/j.1365-3156.2009.02302.x Full text not available from this repository.