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.
Fondell E, Balter O, Rothman KJ. Dietary intake and supplement use of vitamins C and E and upper respiratory tract infection. J Am Coll Nutr. 2011 Aug 1;30(4):248-58.
Fortuny J, Kogevinas M, Zens MS, Schned A, Andrew AS, Heaney J, Kelsey KT, Karagas MR. Analgesic and anti-inflammatory drug use and risk of bladder cancer: a population based case control study. BMC Urol. 2007 Aug 10;7:13. doi: 10.1186/1471-2490-7-13