Aguado J, Campbell A, Ascaso C, Navarro P, Garcia-Esteve L, Luciano JV. Examining the factor structure and discriminant validity of the 12-Item General Health Questionnaire (GHQ-12) among Spanish postpartum women. Assessment. 2012 Dec 19;19(4):517-25.
French M, Neighbors D, Carswell L, Williams R, Bush L. A model for estimating industry compliance costs of food labeling regulations. Agribusiness: An International Journal. 1993;8(2):165-86.