Lennon RP, Fraleigh R, Van Scoy LJ, Keshaviah A, Hu XC, Snyder BL, Miller EL, Calo WA, Zgierska AE, Griffin C. Developing and testing an automated qualitative assistant (AQUA) to support qualitative analysis. Fam Med Community Health. 2021 Nov;9(Suppl 1):e001287. doi: 10.1136/fmch-2021-001287
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.