Wion RK, Hill NL, DePasquale N, Mogle J, Whitaker EB. The relationship between subjective cognitive impairment and activity participation: a systematic review. Act Adapt Aging. 2020;44(3):225-45. doi: 10.1080/01924788.2019.1651188
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.