MARGETTS, B. M. Design concept in nutritional epidemiology. 1991, 153,266
WILLETT, W. C. Reproducibility and validity of a semi - quantitative food frequency questionnaire. Am. J. Epidemiol. 1985, 122, 1, 51
WILLETT, W. C. Validation of a semi-quantitative food frequency questionnaire: Comparison with a 1 - year diet record. Am. Diet. Assoc. 1987, 87, 43
FRCUDENHEIM, J. L. Misclassification of nutrient intake of individuals and groups using one-, two-, three-, and seven-day food records. Am. J. Epidemiol. 1987, 126, 4, 703