^Castillo-Lancellotti, C; Tur, JA; Uauy, R. Impact of folic acid fortification of flour on neural tube defects: a systematic review.. Public Health Nutrition. May 2013, 16 (5): 901–11. PMID 22850218. doi:10.1017/s1368980012003576.
^Canfield, MA; Honein, MA; Yuskiv, N; Xing, J; Mai, CT; Collins, JS; Devine, O; Petrini, J; Ramadhani, TA; Hobbs, CA; Kirby, RS. National estimates and race/ethnic-specific variation of selected birth defects in the United States, 1999–2001.. Birth defects research. Part A, Clinical and molecular teratology. November 2006, 76 (11): 747–56. PMID 17051527. doi:10.1002/bdra.20294.
^Bhide, P; Sagoo, GS; Moorthie, S; Burton, H; Kar, A. Systematic review of birth prevalence of neural tube defects in India.. Birth Defects Research. Part A, Clinical and Molecular Teratology. July 2013, 97 (7): 437–43. PMID 23873811. doi:10.1002/bdra.23153.