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.
Dreyer NA, Loughlin JE, Rothman KJ. Epidemiologic safety surveillance of cellular telephones in the US. Radiat Prot Dosimetry. 1999 Jun;83(1):159-63.