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.
Gray-Little B, Williams VSL, Hancock TD. An item response theory analysis of the Rosenberg self-esteem scale. Pers Soc Psychol Bull. 1997;23(5):443-51. doi: 10.1177/0146167297235001