1. Altman DG (1991): Practical Statistics for Medical Research. London: Chapman & Hall.
2. Beaton GH, Milner J, Corey P, McGuire V, Cousins M, Stewart E, de Ramos M, Hewitt D, Grambsch PV, Kassim N & Little JA (1979): Sources of variance in 24-hour dietary recall data: implications for nutrition study design and interpretation. Am. J. Clin. Nutr. 32, 2546–2549.
3. Belton NR, Macvean ADL, Richards ND, Elton RA, Moffat WMU & Beattie TF (1997): Nutrient intake in Scottish adolescents. Proc. Nutr. Soc. B 56, 303A.
4. Bingham SA, Nelson M, Paul AA, Haraldsdottir J, Björge Löke E & van Staveren WA (1988): Methods for data collection at an individual level, In Manual on Methodology for Food Consumption Studies, eds ME Cameron & WA van Staveren, pp 53–106. Oxford: Oxford University Press.
5. Bland JM & Altman DG (1986): Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1, 307–310.