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.
Purroy F, Cruz Esteve I, Galindo Ortego MG, Marsal Mora JR, Oro M, Plana A. Survey of the knowledge and management of transient ischemic attacks among primary care physicians and nurses. Neurologia. 2011 May;26(4):200-7. doi: 10.1016/j.nrl.2010.04.011