Landmark perspective: An 'extrinsic factor' and pernicious anemia.
D000752:Anemia, Pernicious / Q000209:etiology / Q000266:history* / Q000628:therapy; D000818:Animals; D002417:Cattle; D004285:Dogs; D049673:History, 20th Century; D006801:Humans; D008297:Male; D008875:Middle Aged; D014481:United States; D014805:Vitamin B 12 / Q000266:history*
D014805:Vitamin B 12