RT Journal Article SR Electronic T1 Vitamin D deficiency in the 21st century: a persistent problem among Canadian infants and mothers JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 769 OP 770 DO 10.1503/cmaj.050177 VO 172 IS 6 A1 Ward, Leanne M. YR 2005 UL http://www.cmaj.ca/content/172/6/769.abstract