TY - JOUR T1 - Folic acid supplementation to prevent neural tube defects JF - Canadian Medical Association Journal JO - CMAJ SP - 15 LP - 16 VL - 151 IS - 1 AU - J. P. Welch Y1 - 1994/07/01 UR - http://www.cmaj.ca/content/151/1/15.abstract ER -