RT Journal Article SR Electronic T1 Cobalamin deficiency in elderly patients JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 450 OP 451 DO 10.1503/cmaj.1041424 VO 172 IS 4 A1 Jonathan E. Prousky YR 2005 UL http://www.cmaj.ca/content/172/4/450.2.abstract