Derby CA, Araujo AB, Johannes CB, Feldman HA, McKinlay JB. Measurement of erectile dysfunction in population-based studies: the use of a single question self-assessment in the Massachusetts Male Aging Study. Int J Impot Res. 2000 Aug 1;12(4):197-204.
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.