Usala A L, Madigan T, Burguera B, Sinha M K, Caro J F, Cunningham P, Powell J G, Butler P C
Department of Pediatrics, East Carolina University School of Medicine, Greenville, N.C. 27858-4354.
N Engl J Med. 1992 Sep 17;327(12):853-7. doi: 10.1056/NEJM199209173271205.