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.
Frye S, Crosby M, Edwards TP, Juliano R. US academic drug discovery. Nat Rev Drug Discov. 2011 Jun 1;10(6):409-10. doi: 10.1038/nrd3462