Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians and vegans: results from a cross-sectional analysis of the EPIC-Oxford cohort study. - Gilsing AM; Crowe FL; Lloyd-Wright Z; Sanders TA; Appleby PN; Allen NE; Key TJ; Gilsing, A M J; Crowe, F L; Lloyd-Wright, Z; Sanders, T A B; Appleby, P N; et al. (European Journal of Clinical Nutrition, 2010)