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.
Doward LC, McKenna SP, Meads DM, Jovell AJ, Fisk J, Eckert BJ. The international development of patient reported outcome indices for multiple sclerosis. Poster presented at the 2006 Sixteenth Meeting of the European Neurological Society; May 2006. Lausanne, Switzerland. [abstract] J Neurol. 2006; 253(Suppl 2):125.