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.
McKenna SP, Whalley D, Doward LC. Which outcomes are important in schizophrenia? Int J Methods Psychiatr Res. 2000;9(1):S58-67.