http://www.aafp.org/afp/2011/0615/p1425.html http://www.aafp.org/afp/2011/0615/p1425.html http://www.aafp.org/afp/2011/0615/p1425.html http://www.aafp.org/afp/2011/0615/p1425.html Update on vitamin B12 deficiency http://www.aafp.org/afp/2011/0615/p1425.html Update on vitamin B12 deficiency Update on vitamin B12 deficiency Update on vitamin B12 deficiency Update on Vitamin B12 Deficiency