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.
Milunsky A, Morris JS, Jick H, Rothman KJ, Ulcickas M, Jick SS, Shoukimas P, Willett W. Maternal zinc and fetal neural tube defects. Teratology. 1992 Oct 1;46(4):341-8.
Rothman KJ, Fyler DC. Association of congenital heart defects with season and population density. Teratology. 1976 Feb;13(1):29-34.