Luciano JV, Barrada JR, Aguado J, Osma J, García-Campayo J. Bifactor analysis and construct validity of the HADS: a cross-sectional and longitudinal study in fibromyalgia patients. Psychological Assessment. 2014 Jun;26(2):395-406.
Julvez J, Forns M, Ribas-Fito N, Mazon C, Torrent M, Garcia-Esteban R, Ellison-Loschmann L, Sunyer J. Psychometric characteristics of the California Preschool Social Competence Scale in a spanish population sample. Early Educ Dev. 2008;19(5):795-815.