The EPIC-Norfolk Study

 

Epidemiological assessment of diet: a comparison of a 7-day diary with a food frequency questionnaire using urinary markers of nitrogen, potassium and sodium.

Day N, McKeown N, Wong M, Welch A, and Bingham S

International Journal of Epidemiology. May 2001

(DOI : 10.1093/ije/30.2.309)

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Validation studies in epidemiology: the relative precision of different designs.

Wong M, and Day NE

Journal of epidemiology and biostatistics. Mar 2001

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